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Approve and adopt the 2021 Comprehensive Flood Hazard Management Plan (CFHMP) BEFORE THE BOARD OF COUNTY COMMISSIONERS LEWIS COUNTY, WASHINGTON IN THE MATTER OF: RESOLUTION NO. 21-422 APPROVING AND ADOPTING THE 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN (CFHMP) WHEREAS, the Chehalis River Basin Flood Control Zone District (Flood District) has prepared a Comprehensive Flood Hazard Management Plan (CFHMP); and WHEREAS, an 11-member stakeholder committee of local representatives was assembled to oversee the development of the plan, consisting of Lewis County staff, citizens and representatives of the incorporated towns and cities to meet the requirements and needs of the Federal Emergency Management Agency's (FEMA's) Community Rating System (CRS) program other stakeholders in the planning area; and WHEREAS, an initial scope and feasibility planning effort has been completed to establish the goals and objectives of a comprehensive plan as well as to prepare for and guide future grant opportunities; and WHEREAS, the CFHMP was distributed to the general public for review and comments by the Flood District following an open house and 30-day comment period; and WHEREAS, a State Environmental Policy Act (SEPA) Determination of NonSignificance (DNS) was issued on September 30, 2021, under file number SEP21-0030; and WHEREAS, it appears to be in the best interest to approve and adopt the CFHMP. NOW THEREFORE BE IT RESOLVED that the Lewis County Board of Commissioners officially approves and adopts the attached Comprehensive Flood Hazard Management Plan. DONE IN OPEN SESSION this 30th day of November, 2021. Page 1 of 2 Res. 21-422 APPROVED AS TO FORM: BOARD OF COUNTY COMMISSIONERS Jonathan Meyer, Prosecuting Attorney LEWIS COUNTY, WASHINGTON Amber Smith Lindsey R. Pollock, DVM By: Amber Smith, Lindsey R. Pollock, DVM, Chair Deputy Prosecuting Attorney ATTEST: •' °o"''•was;., Sean D. Swope • • �OPgDOF'. Sean D. Swope, Vice Chair CE 'L ig45 ' . Rieva Lester ••;syN-__-s�.. F. Lee Grose Rieva Lester, F. Lee Grose, Commissioner Clerk of the Lewis County Board of County Commissioners Page 2 of 2 Res. 21-422 -+r 't -• > ..�a'. 'rf _.•, ! _J ..4 .moo . j A]ts \\ / \ Chehalis River Basin Flood Control Zone District Comprehensive Flood Hazard Management Plan FINAL DRAFT 11-16-2021 City of Chehalis - Adopted on Lewis County - Adopted on CRB FCZD - Adopted on 1 441 I ilik . , 'Nast, ---, 1d I ,y z ✓ , .• . ' . •._ ,.!-- • ' .-4,:ilsog .7i . r 00. Ar t fry ~ -`�•."••�`-/ t 1 M - t/( (yam _ 'r' ::y+ ;f)4 �r41:.— ( ,. ,Jr{.... _ , `sti ''., f .-' we 1 , ,,,,*,tof i _ J�' Pi°i J I � �,�•I r (,... �e{,J�r f'.� 'A� I JI i r „:„4 I S PERTEET -, j rir 3. 4» 4�°' IE I TETRA TECH T ACKNOWLEDGMENTS Client Chehalis River Basin Flood Control Zone District Project Team Betsy Dillin, PE Erik Martin, PE Lara McRea Consultants Christina Wollman,AICP, CFM, Perteet Inc. Kirk Holmes, Perteet Inc. Rob Flaner, CFM,Tetra Tech, Inc. Carol Baumann,Tetra Tech, Inc. Stakeholder Committee Tim Fife Hillary Hoke Dan Maughan Betsy Dillin Celeste Wilder Steve Grega Lee Napier Tammy Baraconi Dave Muller Preston Pinkston John Henricksen A.Jason Humphrey Andy Caldwell Bill Brumsickle Alex Rosen Fionna Velazquez Bonnie Canaday Coumbs Chrissy Bailey Emil Pierson Charles Coddington J.Vander Stoep Special Acknowledgments The development of this plan would not have been possible without the dedication and commitment to the process by the Stakeholder Committee.The dedication of the Stakeholder Committee volunteers who graciously allocated their time to this process is greatly appreciated. In addition to the Stakeholder Committee's effort,the Flood Control Zone District and the Comprehensive Flood Hazard Management Plan would not be possible without the citizens of Lewis County. NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN p E RTE E T TABLE OF CONTENTS EXECUTIVE SUMMARY 1 WHAT IS FLOOD HAZARD MITIGATION? 1 PLAN DEVELOPMENT METHODOLOGY 1 GOALS AND OBJECTIVES 3 MITIGATION ACTIONS 3 Implementation 7 PART 1—PLANNING PROCESS AND PROJECT BACKGROUND 8 1.0 INTRODUCTION 8 1.1 WHY PREPARE THIS PLAN 8 1.2 LEWIS COUNTY'S PLANNING AUTHORITY 9 1.3 GUIDELINES FOR FLOOD PLANNING 9 1.3.1 CRS Steps for Comprehensive Flood Hazard Management Plan 9 1.3.2 Flood Control Assistance Account Program(FCAAP)Requirements for Comprehensive Flood Control Management Plan 10 1.4 HOW TO USE THIS PLAN 10 2.0 PLAN DEVELOPMENT METHODOLOGY 12 2.1 FORMATION OF THE PLANNING TEAM 12 2.2 DEFINING THE PLANNING AREA 12 2.3 THE STAKEHOLDER COMMITTEE 13 2.4 COORDINATION WITH OTHER AGENCIES 16 2.5 REVIEW OF EXISTING PROGRAMS 17 2.6 PUBLIC OUTREACH STRATEGY 17 2.6.1 Public Outreach Opportunity#1 17 2.6.2 Public Outreach Opportunity#2 23 2.7 PLAN DEVELOPMENT CHRONOLOGY/MILESTONES 28 3.0 LEWIS COUNTY PROFILE 30 3.1 HISTORICAL OVERVIEW 30 3.1.1 Native Americans(ICR Section 3.6.1, Herrera,2013) 30 3.1.2 Euro-American Settlement(ICR Section 3.6.2, Herrera,2013) 31 3.1.3 Historic Uses of the River and Floodplain 32 3.2 PHYSICAL SETTING 32 3.2.1 Watersheds 33 3.2.2 Geology 35 3.2.3 Climate 37 3.2.4 Fish and Wildlife 38 3.3 DEVELOPMENT FEATURES 40 3.3.1 Land Use 40 3.3.2 Critical Facilities and Infrastructure 41 3.4 DEMOGRAPHICS 44 3.4.1 Population Characteristics 44 3.4.2 Age Distribution 46 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T 3.4.3 Race, Ethnicity, and Language 47 3.4.4 Disabled Populations 48 3.5 ECONOMY 49 3.5.1 Income 49 3.5.2 Industry, Businesses, and Institutions 49 3.5.3 Employment Trends and Occupations 50 4.0 REGIONAL CONSISTENCY 53 4.1 REGIONAL PLAN COORDINATION 53 4.2 REGIONAL PLAN CONSISTENCY REVIEW 54 PART 2—RISK ASSESSMENT 55 5.0 RISK ASSESSMENT METHODOLOGY 55 5.1 PURPOSE OF RISK ASSESSMENT 55 5.2 RISK ASSESSMENT APPROACH 56 5.2.1 FEMA's Hazus Software 56 5.2.2 Sources of Data Used in Hazus Modeling 57 5.2.4 Limitations 58 6.0 LEWIS COUNTY FLOOD PROFILE 60 6.1 GENERAL CONCEPTS 60 6.1.1 Measuring Floods and Floodplains 60 6.1.2 Floodplain Ecosystems 61 6.2 PRINCIPAL TYPES OF FLOODING IN THE CHEHALIS RIVER BASIN 61 6.2.1 Stage Flooding 61 6.2.2 Flash Flooding 62 6.3 MAJOR FLOOD EVENTS 62 6.3.1 2007 Chehalis River Flood 63 6.3.2 Other Historical Flooding Events 65 6.4 LOCATION 66 6.5 FREQUENCY 71 6.6 SEVERITY 73 6.7 WARNING TIME 73 6.7.1. Lewis County Flood Warning System 73 6.7.2 Flood Watch and Warning System 76 6.8 SECONDARY HAZARDS 76 6.8.1 Landslides 76 6.8.2 Erosion 79 6.8.3 Other Hazards 79 6.9 FUTURE TRENDS 79 6.10 SCENARIO 80 6.11 CHALLENGES,GAPS,AND ISSUES 80 7.0 FLOOD HAZARD EXPOSURE 82 7.1 POPULATION 82 7.2 PROPERTY 83 I I NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN p E RTE E T 7.2.1 Structures in the Floodplain 83 7.2.2 Exposed Value 85 7.3 CRITICAL FACILITIES AND INFRASTRUCTURE 88 7.3.1 Hazardous Materials Facilities 88 7.3.2 Utilities and Infrastructure 88 7.3.3 Critical Facilities 93 7.4 ENVIRONMENT 94 8.0 FLOOD HAZARD VULNERABILITY 96 8.1 POPULATION 96 8.1.1 Vulnerable Populations 96 8.1.2 Public Health and Safety 96 8.2 PROPERTY 98 8.2.1 Loss Estimates 98 8.2.2 National Flood Insurance Program 100 8.2.4 Repetitive Loss 102 8.3 CRITICAL FACILITIES AND INFRASTRUCTURE 105 8.4 ENVIRONMENT 105 9.0 CLIMATE CHANGE CONSIDERATIONS FOR FLOOD HAZARD MANAGEMENT 107 9.1 WHAT IS CLIMATE CHANGE? 107 9.2 HOW CLIMATE CHANGE AFFECTS FLOOD HAZARD MANAGEMENT 108 9.3 CURRENT INDICATIONS AND OBSERVED CHANGES 109 9.3.1 Observed Global Changes 109 9.3.2 Observed Changes in the Pacific Northwest 109 9.4 FUTURE IMPACTS 110 9.4.1 Global Projections 110 9.4.2 Projections and Potential Impacts for the Pacific Northwest 110 9.4.3 Projections and Potential Impacts for the Chehalis River Basin 111 9.5 IMPACTS ON FLOOD-RELATED HAZARDS 112 9.5.1 Flood 112 9.5.2 Dam Failure 113 9.5.3 Wildfire 113 9.6 RESPONSES TO CLIMATE CHANGE 113 PART 3—MITIGATION STRATEGY 115 10.0 GOALS AND OBJECTIVES 115 10.1 GOALS 115 10.2 OBJECTIVES 115 11.0 POLICIES 116 11.1 GENERAL POLICIES 116 11.1.1 Flood Hazard Management 116 11.1.2 Policies for Regional Consistency 118 11.2 FLOOD HAZARD AREA LAND USE POLICIES 118 11.2.1 Changes to Flood Hazard Areas Based on Future Conditions 119 III NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T 11.3 FLOOD RISK REDUCTION POLICIES 119 11.4 FUNDING AND FINANCING POLICIES 120 12.0 MITIGATION ACTIONS 122 12.1 ALTERNATIVES ANALYSIS 122 12.1.1 Mitigation Alternative Catalog 122 12.1.2 Past Action Review 122 12.1.3 Action Selection 123 12.2 MITIGATION ACTION PLAN 123 12.3 BENEFIT/COST REVIEW 128 12.4 ACTION PLAN PRIORITIZATION 129 12.5 ANALYSIS OF MITIGATION ACTIONS 130 12.6 ACTION#1-CHEHALIS BASIN STRATEGY 131 12.6.1 Flood Retention Facility 131 12.6.2 Airport Levee 133 12.6.3 Economic Benefit of Flood Reduction Projects 135 PART 4-PLAN MAINTENANCE 137 13.0 ADOPTION 137 14.0 PLAN MAINTENANCE STRATEGY 138 14.1 PLAN IMPLEMENTATION 138 14.2 STAKEHOLDER COMMITTEE 138 14.3 ANNUAL PROGRESS REPORT 139 14.4 PLAN UPDATE 139 14.5 CONTINUING PUBLIC INVOLVEMENT 140 14.6 INCORPORATION INTO OTHER PLANNING MECHANISMS 140 15.0 REFERENCES 142 LIST OF FIGURES FIGURE 2-1.PLANNING AREA. 13 FIGURE 2-2.PUBLIC OUTREACH#1-STORY MAP PAGES. 19 FIGURE 2-3.PUBLIC OUTREACH#1-EMAIL RELEASE. 22 FIGURE 2-4.FCZD WEBSITE. 23 FIGURE 2-5.PUBLIC OUTREACH#2-PRESS RELEASES. 24 FIGURE 2-6.UPDATED FCZD WEBSITE. 25 FIGURE 2-7.MAP STATION EXAMPLE 25 FIGURE 2-8.PUBLIC OUTREACH#2-STORY MAP PAGES. 26 FIGURE 3-1.MAP OF CRITICAL FACILITIES AND INFRASTRUCTURE 43 FIGURE 3-2.WASHINGTON AND LEWIS COUNTY POPULATION CHANGE 45 FIGURE 3-3.LEWIS COUNTY AGE DISTRIBUTION 47 FIGURE 3-4.LEWIS COUNTY RACE DISTRIBUTION. 48 FIGURE 3-5.INDUSTRY IN LEWIS COUNTY. 50 FIGURE 3-6.US,WASHINGTON,AND LEWIS COUNTY UNEMPLOYMENT RATE. 51 FIGURE 3-9.OCCUPATIONS IN LEWIS COUNTY. 52 IV NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T FIGURE 6-1.THE SCIENCE BEHIND ATMOSPHERIC RIVERS. 62 FIGURE 6-2.SATELLITE PHOTO OF DECEMBER 2007 STORM SYSTEM 64 FIGURE 6-3.100-YEAR EFFECTIVE FLOODPLAIN WITH FLOODWAY 67 FIGURE 6-4.100-YEAR EFFECTIVE FLOODPLAIN(DFIRM)WITH FLOOD ZONES. 68 FIGURE 6-5.100-YEAR MODELED FLOODPLAIN 69 FIGURE 6-6.100-YEAR CLIMATE CHANGE FLOODPLAIN. 70 FIGURE 6-7.10-YEAR MODELED FLOODPLAIN. 71 FIGURE 6-8.PERCENTAGE OF HISTORICAL CRESTS OCCURRING IN EACH MONTH. 72 FIGURE 6-9.HISTORICAL CRESTS PER YEAR. 72 FIGURE 6-10.FLOOD INUNDATION MAPPING 74 FIGURE 6-11.GAGE ALERT LOCATIONS WITHIN LEWIS COUNTY. 75 FIGURE 6-12.CENTRALIA WEBCAM. 75 FIGURE 6-13.WATER AND LANDSLIDES 77 FIGURE 6-14.RECORDED LANDSLIDES IN THE HEADWATERS OF THE CHEHALIS RIVER BASIN AS A RESULT OF THE 2007 STORM. 78 FIGURE 7-1.DIFFERENCES BETWEEN EFFECTIVE AND MODELED FLOODPLAIN. 83 FIGURE 7-2.SKOOKUMCHUCK DAM INUNDATION AREA. 92 FIGURE 8-1.LEWIS COUNTY REPETITIVE LOSS AREAS. 103 FIGURE 8-2.CHEHALIS REPETITIVE LOSS AREAS 104 FIGURE 9-1.CARBON DIOXIDE CONCENTRATIONS OVER TIME. 108 FIGURE 9-2.MID-RANGE CLIMATE CHANGE PROJECTIONS 112 FIGURE 12-1.FLOOD RETENTION FACILITY PROJECT. 132 FIGURE 12-2.FLOODING REDUCTION AS A RESULT OF FLOOD RETENTION FACILITY 133 FIGURE 12-3.AIRPORT LEVEE PROJECT. 134 FIGURE 12-4.FLOODING REDUCTION AS A RESULT OF FLOOD RETENTION FACILITY AND AIRPORT LEVEE 135 FIGURE 13.1.FCZD ADOPTION RESOLUTION. 137 FIGURE 13.2.LEWIS COUNTY COMMISSIONERS ADOPTION RESOLUTION. 137 FIGURE 13.3.CHEHALIS CITY COUNCIL ADOPTION RESOLUTION. 137 LIST OF TABLES TABLE ES-1.SUMMARY OF HAZARD MITIGATION ACTIONS. 4 TABLE 2-1.STAKEHOLDER COMMITTEE. 14 TABLE 2-2.STAKEHOLDER EXPERIENCE. 15 TABLE 2-3.STAKEHOLDER MEETING ATTENDANCE RECORDS. 15 TABLE 2-4.PLAN DEVELOPMENT MILESTONES 28 TABLE 3-1.CRITICAL FACILITIES WITHIN THE CHEHALIS RIVER BASIN 42 TABLE 3-2.CRITICAL INFRASTRUCTURE WITHIN THE CHEHALIS RIVER BASIN 42 TABLE 3-3.RECENT LEWIS COUNTY POPULATION GROWTH 45 TABLE 3-4.PROJECTED FUTURE LEWIS COUNTY POPULATION. 46 TABLE 5-1.HAZUS MODEL DATA DOCUMENTATION. 58 TABLE 6-1.PRESIDENTIAL DISASTER DECLARATIONS IN LEWIS COUNTY. 63 TABLE 6-2.DISCHARGE RATES AT THE GRAND MOUND GAGING STATION. 73 TABLE 6-3.NATIONAL WEATHER SERVICE FLOOD STAGES 76 V NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN p E RTE E T TABLE 7-1.TOTAL AREA AND NUMBER OF STRUCTURES IN THE 100-YEAR FLOODPLAINS BY MUNICIPALITY. 84 TABLE 7-2.TOTAL AREA AND NUMBER OF STRUCTURES IN THE 10-YEAR FLOODPLAIN BY MUNICIPALITY. 85 TABLE 7-3.TOTAL VALUE OF STRUCTURES AND CONTENT IN THE 100-YEAR FLOODPLAINS BY MUNICIPALITY 85 TABLE 7-4.TOTAL VALUE OF STRUCTURES IN THE 10-YEAR FLOODPLAIN BY MUNICIPALITY. 86 TABLE 7-5.ZONING IN THE FLOODPLAIN—CITY OF CHEHALIS 86 TABLE 7-6.ZONING IN THE FLOODPLAIN—CITY OF CENTRALIA 87 TABLE 7-7.ZONING IN THE FLOODPLAIN—CITY OF NAPAVINE. 87 TABLE 7-8.ZONING IN THE FLOODPLAIN—CITY OF PE ELL 87 TABLE 7-9.ZONING IN THE FLOODPLAIN—UNINCORPORATED COUNTY(CHEHALIS BASIN). 88 TABLE 7-10.CRITICAL INFRASTRUCTURE WITHIN THE FLOODPLAIN. 89 TABLE 7-11.LEVEE PROFILES 93 TABLE 7-12.CRITICAL FACILITIES WITHIN THE FLOODPLAIN 94 TABLE 8-1.NUMBER OF PERSONS DISPLACED OR REQUIRING SHELTER. 98 TABLE 8-2.LOSS ESTIMATES FOR 100-YEAR FLOOD EVENTS 99 TABLE 8-3.LOSS ESTIMATES FOR 10-YEAR MODELED FLOOD EVENT. 100 TABLE 8-4.FLOOD INSURANCE STATISTICS FOR LEWIS COUNTY. 101 TABLE 8-5.ESTIMATED RESIDENTIAL PENETRATION RATE WITHIN CITIES 101 TABLE 8-6.FLOOD INSURANCE CLAIMS WITH PAYMENT BEGINNING 11/1978 101 TABLE 8-7.REPETITIVE LOSS PROPERTIES AS OF MAY 21,2021. 102 TABLE 8-8.VULNERABLE CRITICAL FACILITIES(CATASTROPHIC FLOOD). 105 TABLE 8-9.ESTIMATED FLOOD-CAUSED DEBRIS. 106 TABLE 12-1.FLOOD MITIGATION ACTION PLAN MATRIX. 124 TABLE 12-2.PRIORITIZATION OF MITIGATION ACTIONS. 129 TABLE 12-3.MITIGATION ACTIONS ANALYSIS 131 TABLE 12-4.ECONOMIC IMPACTS OF FLOOD REDUCTION PROJECT. 136 LIST OF APPENDICES APPENDIX A Relevant Programs and Regulations APPENDIX B Description of CRS and FCAAP Planning Guidelines APPENDIX C Public Outreach Survey Results and Summaries APPENDIX D Mitigation Action Alternatives Catalog APPENDIX E Annual Progress Report Template vi NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T EXECUTIVE SUMMARY Flooding is a major concern in the Chehalis River Basin within Lewis County. Flood events have caused millions of dollars in damage, lost commerce, and disrupted lives. Recent events and the formation of the Chehalis River Basin Flood Control Zone District(FCZD) have prompted the FCZD to update this Flood Plan.The FCZD needs a comprehensive plan to guide its operations.This Flood Plan will serve as a guidance document for the FCZD by providing regional policies, programs, and projects to reduce the risk to people and property from river and stream flooding within the Chehalis River Basin. It presents a long-term vision for managing all flood hazards in Lewis County's Chehalis River Basin and recommends near-term actions to achieve that vision.The Flood Plan recommends actions the FCZD, Lewis County, the Cities of Centralia, Chehalis,and Napavine, and the Town of Pe Ell may take to reduce flood risks and to protect, restore,or enhance riparian and aquatic ecosystems. What is Flood Hazard Mitigation? Mitigation is defined as "sustained action taken to reduce or eliminate long-term risk to life and property." It involves strategies such as planning, policy changes, programs, projects, and other activities to address risk from hazards in a planning area.The responsibility for hazard mitigation lies with many, including private property owners, business, industry, and local, state, and federal government. Recognizing that there is no one solution for mitigating flood hazards, planning provides a mechanism to identify the best alternatives within the capabilities of a jurisdiction.A flood hazard management plan achieves the following to set the course for reducing the risk associated with flooding: • Ensuring that all possible activities are reviewed and implemented so that local problems are addressed by the most appropriate and efficient solutions. • Ensuring that activities are coordinated with each other and with other community goals and activities, preventing conflicts and reducing the cost of implementing each individual activity. • Coordinating local activities with federal, state, and regional programs. • Educating residents on the hazards, loss reduction measures, and natural and beneficial functions of their floodplains. • Building public and political support for mitigation projects. • Fulfilling planning requirements for obtaining state or federal assistance. • Facilitating the implementation of floodplain management and mitigation activities through an action plan that has specific tasks,staff assignments, and deadlines. The Chehalis River Basin Comprehensive Flood Hazard Management Plan identifies policies and actions chosen through a facilitated process that focused on meeting these objectives. Plan Development Methodology Development of the Chehalis River Basin Comprehensive Flood Hazard Management Plan included five phases: • Phase 1, Organize and review—An 11-member Stakeholder Committee of local representatives was assembled to oversee the development of the plan, consisting of County staff, citizens, and other stakeholders in the planning area.A planning team consisting of key County staff as well 1 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T as a technical consultant was assembled to provide technical support to the Stakeholder Committee. Full coordination with other county, state, and federal agencies involved in flood hazard mitigation occurred from the outset of this plan's development through its completion. A multimedia public involvement strategy centered on a hazard preparedness questionnaire was implemented. A comprehensive review was performed of existing plans and programs that can support flood hazard mitigation.A key function of the Stakeholder Committee was to identify guiding principles, goals, and objectives for the Flood Plan. • Phase 2, Flood Hazard Risk Assessment—Risk assessment is the process of measuring the potential loss of life, personal injury, economic injury, and property damage resulting from natural hazards.This process assesses the vulnerability of people, buildings, and infrastructure to natural hazards. It focuses on the following parameters: o Hazard profiling o The impact of hazards on physical, social, and economic assets o Vulnerability identification o Estimates of the cost of damage or cost that can be avoided through mitigation • The flood hazard risk assessment for this Flood Plan meets the requirements outlined in Chapter 44 of the Code of Federal Regulations as well as the requirements for flood hazard assessment included in the Federal Emergency Management Agency's(FEMA's)Community Rating System (CRS). • Phase 3, Engage the public—The Stakeholder Committee developed a public involvement strategy to maximize the capabilities of the County.This strategy was implemented by the planning team and included two public meetings early in the planning process, a public meeting to review the draft plan, a hazard mitigation survey, a County-sponsored website dedicated to the plan, and multiple media releases.This strategy was a key element in the success of the planning effort. • Phase 4,Assemble the updated plan—The Planning Team and Stakeholder Committee assembled key information from Phases 1 and 2 into a document to meet CRS requirements. Under the CRS, a flood hazard management plan must include the following: o A description of the planning process o A risk assessment o A mitigation strategy including goals, a review of alternatives, and a prioritized action plan o A plan maintenance section o Documentation of adoption • Phase 5, Plan adoption—Upon completion of Phase 4,a pre-adoption review draft of the Flood Plan will be sent to the Insurance Services Office (ISO), FEMA's Community Rating System (CRS) contractor,for review and comment. Once pre-adoption approval has been granted by ISO,the final adoption phase will begin.The Flood Plan includes a plan implementation and maintenance section that details the formal process for ensuring that the plan remains an active and relevant document.The plan maintenance process includes a schedule for monitoring and evaluating the plan's progress annually and producing a plan revision every five years.This phase includes strategies for continued public involvement and incorporation of the Flood Plan recommendations into other County planning mechanisms, such as the comprehensive plan, capital improvement plan, and the Lewis County Hazard Mitigation Plan. 2 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T This plan is an update to the 2008 Lewis County Comprehensive Flood Hazard Management Plan.The 2008 plan was a comprehensive update of the 2001 and 1994 plans. Relevant components of the 2008 plan have been carried over to this plan, which applies only to the Chehalis River Basin within Lewis County. In addition, information relevant to Lewis County was gathered from several of the studies and other documents that have been prepared for activities related to the Chehalis Basin Flood Authority and recently formed Office of the Chehalis Basin. Goals and Objectives Through a facilitated process,the Stakeholder Committee identified goals and objectives. These planning components all directly support one another. Goals were selected that meet County and city priorities, and objectives were identified that fulfill multiple goals. Goals: 1. Reduce and minimize flood related hazards to the public and emergency responders. 2. Reduce and minimize flood damage and financial impacts to the community. 3. Avoid impacts that cause flooding of downstream neighbors. 4. Avoid, minimize, or mitigate environmental impacts of flood hazard reduction activities. 5. Increase public awareness and understanding of flooding. Objectives: 1. Utilizing the best available data and science, continually improve and annually review plans for mitigating and minimizing flood damage impacts. 2. Identify and support flood damage mitigation projects that provide the highest cost benefit and greatest protection, and avoid, minimize,or mitigate impacts on the environment. 3. Communicate flood damage risk to the public, including increased risk due to climate change, and encourage that future development recognize and minimize this risk. 4. Consider floodplain management policies that promote resiliency and sustainable operations of identified critical facilities. 5. Support the current Chehalis Basin Strategy and the Lewis County Shoreline Master Program to enhance aquatic species and restore habitat in the floodplain. 6. Promote and maintain partnerships among all levels of government, including tribal governments, and the business community to coordinate mutually beneficial mitigation strategies. 7. Continue to improve systems that provide warning and emergency communications. 8. Enhance all facets of partnership emergency response capabilities, including flood damage mitigation of vulnerable critical facilities and infrastructure. Mitigation Actions The flood hazard mitigation action plan is a key element of this plan. It is through the implementation of the action plan that Lewis County can strive to become flood disaster-resilient through sustainable hazard mitigation.The action plan includes an assessment of the capabilities of the FCZD, County, and 3 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T Cities to implement hazard mitigation actions, a review of alternatives, a prioritization schedule, and a mitigation strategy matrix that identifies the following: • Description of the action • Objectives addressed • Lead implementation agency(or agencies) • Estimated benefits • Estimated costs • Timeline for implementation • Funding sources • Prioritization For the purposes of this document, mitigation actions are defined as activities designed to reduce or eliminate losses resulting from the impacts of flooding. Mitigation actions may be implemented by one or more of the agencies that participated in this planning effort. Not all mitigation actions apply to all agencies. Although one of the driving influences for preparing this plan was the CRS program and receiving more CRS credit to improve the rating of participating communities,this plan does not focus solely on CRS credits. It was important to the FCZD and the Stakeholder Committee to examine actions that would work through all phases of emergency management and flood risk reduction. Some of the actions outlined in this plan fall outside CRS credit criteria, and CRS creditability was not the focus of their selection. Rather,the focus was on the actions' effectiveness in achieving the goals of the Flood Plan and whether they are within the FCZD's, County's, and Cities' capabilities.Table ES-1 presents a summary of the identified hazard mitigation actions. Table ES-1. Summary of Hazard Mitigation Actions. Action# Description Priority Continue participation and implementation of the flood damage reduction projects 1 that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis High Basin. 2 Develop a technical assistance program to support landowners with bank stabilization High and/or post-disaster debris removal. Develop a Newaukum Unit Drainage Basin Plan for Dillenbaugh, Dilly,and Berwick Creeks. Develop a comprehensive drainage basin plan to identify cost effective and 3 feasible structural and non-structural actions that will minimize future peak flow Medium increases.The study should include the area between Armstrong Road and Jackson Highway adjacent to Logan Hill Road. Identify sources of local funding for the FCZD to fund FCZD administration and 4 leverage alternative funding sources. High S Identify alternative sources of funding to leverage FCZD funding to perform new flood Low studies in identified areas of need based on risk. As FCZD projects are constructed, monitor projects using identified performance 6 measures and adaptive management to track the effectiveness of completed projects Medium to inform the design and implementation of future projects. When requested, FCZD may act as the applicant agent for mitigation grant Medium opportunities for private property requesting to participate in grant programs. 4 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Action# Description Priority Maximize federal,state,and local funding opportunities through grant application 8 submittals in support of capital improvement projects,technical studies,and other Low flood hazard management activities. 9 Mitigate flood related risk to publicly owned County and City bridges. Low 10 Maintain database of flood control needs within the planning area as needs become High identified for incorporation into future updates and progress reporting to this plan. Inform future mapping,grant applications,studies,and other activities by 11 maintaining a database on known flood risk that tracks historical flood conditions to High include, but not be limited to: high water marks, recorded damages, photos, observed flood conditions,etc. Utilizing the best available data,science,and technology,maintain and enhance,as 12 data becomes available,the Level 2,user-defined Hazus-MH model that was High constructed to support this planning effort. Offer the Chehalis River Basin Comprehensive Flood Hazard Management Plan as information available for integration into other appropriate plans and programs that can support or enhance the participating jurisdictions efforts to reduce flood risk as 13 High these plans and programs are updated. Examples of such plans/programs would include but are not limited to: Lewis County Hazard Mitigation Plan, Lewis County Comprehensive Plan,and Lewis County Shoreline Master Program. 14 Lewis County and the Cities of Centralia and Chehalis will continue participating in the High Community Rating System (CRS)process. g 15 Deploy public information and outreach program targeting at risk properties within High the planning area. 16 Coordinate with FEMA Region X on deploying flood insurance workshops for agents, High lenders,and citizens within the performance period for this plan. Participate and coordinate with the Office of the Chehalis Basin,the Chehalis River 17 Basin Flood Authority,and other pertinent Chehalis Basin organizations to ensure High projects and programs are consistent with larger basin-wide objectives. 18 Participate in updates to the County's Flood Insurance Rate Maps to ensure the maps accurately reflect local conditions. Medium 19 Include CMZs,dam and levee breach inundation areas,and other critical areas as Medium informational layers in the County's online public web map. 20 Encourage FEMA and NFIP training for County and City staff that administer High floodplain regulations and FEMA grant programs. Provide outreach and educational materials for the public on flood hazards, risks of development in floodplains, NFIP regulations,and flood mitigation programs, 21 including annual mailings to flood prone properties and placing flood information at High local libraries. Maintain the flood information website on the FCZD web page to provide Chehalis 22 River Basin information and links to the flood warning system and all other related High websites and information. 23 Maintain an inventory of properties located in the floodplain. High Continue to support projects that evaluate the feasibility of regional stormwater detention facilities to address increased stormwater runoff for development in the 24 basins that occurred prior to implementation of site-specific stormwater High management measures Maintain a database of properties that experience repetitive flooding,to include 25 properties identified as Repetitive Loss(RL)properties.The County will establish a High procedure for updating the list annually or following a flood event as necessary.The 5 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Action# Description Priority database will be used to establish a prioritized list of properties that would benefit from mitigation or acquisition,and to provide the owners of the properties information about available funding. Participate in developing flood control projects with other entities such as the 26 Chehalis River Basin Flood Authority,Office of the Chehalis Basin, USACE,and the Low Washington State Department of Transportation (WSDOT). Perform a field examination of all flood control structures and create a database of 27 the information, including ownership and maintenance responsibilities. Determine Medium the maintenance responsibility of each structure. 28 Support projects that would mitigate or relocate utilities and critical facilities which Low are subject to flooding. 29 Encourage NIMS/ICS training for County staff that may work within or interact with High the Emergency Operations Center(EOC). g Develop a flood response plan that includes response and recovery roles, responsibilities,and priorities,flood early warning system procedures, pre-identified 30 detour routes,criteria to assist emergency response personnel in determining what Medium actions are appropriate when providing assistance to private property during the response and recovery phases,and a list of not-for-profit essential service providers that provide community support during and after a flood event. Develop and/or review adequacy of mutual aid agreements and procure on-call 31 Medium service contracts to assist with demand for human resources following a disaster. Maintain a database of all known past problem areas.This database should be linked to GIS for easy visual examination.The County should update the database after each 32 flood event to ensure that the information is captured for future mitigation grant High opportunities. Assign a staff member to become familiar with the FEMA Stafford Act Section 406 33 mitigation assistance program and identify potential new mitigation funding Medium opportunities. Coordinate with WA EMD to ensure County staff attends annual preliminary damage 34 Medium assessment and Public Assistance Grant Program training. 35 Prevent adverse impacts to the floodplain by requiring all new commercial,industrial, High multi-family,and subdivisions to demonstrate no adverse impact. g Continue to maintain good standing under the National Flood Insurance Program by implementing programs that meet or exceed the minimum NFIP requirements.Such 36 programs include enforcing an adopted flood damage prevention ordinance, Medium participating in floodplain mapping updates,and providing public assistance and information on flood hazard requirements and impacts. Develop a communication protocol plan and provide training to all County and city 37 Medium responders on new protocol and system upgrades as funding becomes available. 38 Map detour routes and share routes with WSDOT to assist in efficient detour High planning. g 39 Support updates to the flood warning system to ensure it utilizes the best available High data,science,and technology. g 40 Utilize the best available data,science,and technology in District led projects, Low programs,and outreach. 6 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Implementation Full implementation of the recommendations of this plan will require time and resources. This plan reflects an adaptive management approach in that specific recommendations and plan review protocols are provided to evaluate changes in vulnerability and action plan prioritization after the Flood Plan is adopted.The true measure of the plan's success will be its ability to adapt to the ever-changing climate of hazard mitigation. Funding resources are always evolving, as are programs based on state or federal mandates. Lewis County has a long-standing tradition of progressive, proactive response to issues that may impact its citizens.This tradition is reflected in the development of this plan.The Chehalis River Basin Flood Control Zone District Board of Supervisors will assume responsibility for adopting the recommendations of this plan and committing resources toward implementation of actions that are the responsibility of the FCZD and supporting the implementation of actions that are the responsibility of other agencies.The framework established by this plan will help to identify strategies to maximize the potential for implementation based on available and potential resources. It encourages the responsible agencies to pursue mitigation projects when the project benefits exceed the project costs.The FCZD developed this plan with extensive public input.These techniques will set the stage for successful implementation of the recommendations in this plan. 7 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T PART 1 — PLANNING PROCESS AND PROJECT BACKGROUND 1.0 INTRODUCTION 1.1 Why Prepare this Plan Flood hazard mitigation is a way to reduce or alleviate the loss of life, personal injury, and property damage that can result from flooding through long-and short-term strategies. It involves strategies such as planning, policy changes, programs, projects, and other activities that can mitigate the impacts of floods.The responsibility for flood hazard mitigation lies with many, including private property owners, business, industry, and local, state, and federal government. Numerous state and federal programs and regulations promote comprehensive flood hazard management planning. Notable among these is the Federal Emergency Management Agency's(FEMA) Community Rating System (CRS) program.This program that is part of the National Flood Insurance program (NFIP), provides benefits in the form of reduced flood insurance costs for communities that meet minimum requirements for flood hazard management. The Chehalis River Basin Comprehensive Flood Hazard Management Plan (the Flood Plan) recommends regional policies, programs, and projects to reduce the risk to people and property from river flooding and channel migration in Lewis County.This plan presents a long-term vision for managing all flood hazards within the portion of the Chehalis River Basin that is within Lewis County and recommends specific near-term actions to achieve that vision.The Flood Plan recommends actions the FCZD, Lewis County, and cities in the County may take to reduce flood risks and to protect, restore or enhance riparian and aquatic ecosystems. Lewis County and the Cities of Centralia, Chehalis, and Napavine, and Town of Pe Ell participate in the NFIP. Flooding has been an ongoing hazard in the County. Historical records indicate that minor flooding occurs every two to five years, and major flooding every ten years. Yes, major floods occurred in 2007 and again in 2009.The 2007 flood caused an estimated $500 million in public and private property damage in the County. Data suggests that flood frequency and intensity are increasing. Current estimates range from an 18 percent to 90 percent increase in peak flows. (WA Ecology, 2016). Considering this, the County formed a Flood Control Zone District (FCZD) in 2011 to support flood hazard management, and the State formed the Chehalis Basin Work Group.The Chehalis Basin Work Group led to the formation of the Chehalis River Basin Flood Authority and the Office of the Chehalis Basin and millions of dollars of state funding to perform flood reduction projects throughout the watershed. Recent efforts led by the Office of the Chehalis Basin involving the FCZD have demonstrated the need to update this Flood Plan.The Flood Plan complies with state and federal requirements for flood hazard management and meets the specific near-term planning needs of Lewis County for flood control. It identifies resources, information, and strategies for reducing risk from flood hazards, and will help guide and coordinate mitigation activities.The Flood Plan was developed to meet the following objectives: • Meet the needs of the FCZD, Lewis County, and state and federal requirements. • Coordinate existing plans and programs so that high-priority actions and projects to mitigate possible flood impacts are funded and implemented. 8 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • Create a linkage between the Flood Plan and other established City, County,and state plans so that they can work together for successful mitigation. All citizens and businesses of Lewis County are the ultimate beneficiaries of this plan.The plan's goals and recommendations lay the groundwork for development and implementation of local mitigation activities and partnerships. 1.2 Lewis County's Planning Authority The Revised Code of Washington (RCW, Section 86.12.210) authorizes county legislative bodies in Washington to adopt comprehensive flood control management plans for any drainage basin wholly or partially within the county.The Flood Plan must meet NFIP participation requirements (44 CFR Part 60.3) and Washington Department of Ecology flood hazard management requirements (Chapter 86.26 RCW, Chapter 86.16 RCW, and Washington Administrative Code (WAC) Chapter 173-145).The Lewis County Chehalis Basin Comprehensive Flood Hazard Management Plan will be adopted by reference in the Lewis County Comprehensive Plan for protection of frequently flooded areas, as required by Washington's Growth Management Act.The comprehensive flood hazard management plan also functions as the updated flood hazard portion of the Lewis County Multi-Jurisdictional Hazard Mitigation Plan, which was adopted for compliance with the federal Disaster Mitigation Act of 2000. 1.3 Guidelines for Flood Planning The priority for this plan is to benefit the citizens of Lewis County by providing the greatest possible protection against the hazard posed by flooding in the Chehalis River Basin. In addition,the Flood Plan has been developed to follow as closely as feasible the guidelines for flood planning for the Community Rating System (CRS) and by Washington State for the Flood Control Assistance Account Program (FCAAP). 1.3.1 CRS Steps for Comprehensive Flood Hazard Management Plan Developing a comprehensive flood hazard management plan is among the activities that earn CRS credits toward reduced flood insurance rates.To earn CRS credit for a flood hazard management plan, the community's process for developing the Flood Plan must include at least one item from each of 10 steps (see Appendix A for details): • Planning process steps: o Step 1, Organize o Step 2, Involve the public o Step 3, Coordinate • Risk assessment steps: o Step 4,Assess the hazard o Step 5,Assess the problem • Mitigation strategy steps: o Step 6, Set goals o Step 7, Review possible activities 9 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T o Step 8, Draft an action plan • Plan maintenance steps: o Step 9,Adopt the plan o Step 10, Implement, evaluate, and revise 1.3.2 Flood Control Assistance Account Program (FCAAP) Requirements for Comprehensive Flood Control Management Plan Eligibility for Washington's FCAAP funding for flood projects requires that the requesting jurisdiction complete a comprehensive flood control management plan.The Flood Plan must include six components, as summarized below, and described in detail in Appendix A: • Determination of the need for flood control work. • Description of alternative flood control work, including potential in-stream measures and alternatives to in-stream measures. • Identification and consideration of potential impacts of in-stream flood control work on the in- stream uses and resources. • Area of coverage shall include, at a minimum,the area of the 100-year floodplain within a reach of the watershed of sufficient length to ensure that a comprehensive evaluation can be made of the flood problems for a specific reach of the watershed, as well as flood hazard areas not subject to riverine flooding(e.g., coastal flooding,flash flooding, or flooding from inadequate drainage) • Conclusion and proposed solutions. • Certification from the Department of Commerce that the local emergency management organization is administering an acceptable comprehensive emergency operations plan. 1.4 How to Use this Plan This Comprehensive Flood Hazard Management Plan is organized into the following primary parts, which follow the organization of the CRS steps for flood hazard management planning: • Part 1—Planning Process and Project Background • Part 2—Risk Assessment • Part 3—Mitigation Strategy • Part 4—Plan Maintenance Each part includes elements identified in the CRS's 10 steps.These steps are often cited at the beginning of a subsection to illustrate compliance with the requirement. The following appendices provided at the end of the Flood Plan include information or explanations to support the main content of the plan: • Appendix A—Relevant Programs and Regulations • Appendix B—Description of CRS and FCAAP planning guidelines • Appendix C—Public outreach information, including the survey and summary and documentation of public meetings 10 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • Appendix D—Mitigation Actions Alternative Catalog • Appendix E—A template for progress reports to be completed as this plan is implemented 11 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 2.0 PLAN DEVELOPMENT METHODOLOGY This chapter describes key parameters, participants and agreements for the following steps followed in developing the Chehalis River Basin Comprehensive Flood Hazard Management Plan: • Form a planning team • Define the planning area • Establish a Stakeholder Committee • Coordinate with other agencies • Review existing programs • Engage the public 2.1 Formation of the Planning Team This planning project was initiated and overseen by the FCZD.The County hired Perteet Inc. and Tetra Tech, Inc. to assist with plan development and implementation.A planning team was formed to lead the planning effort, made up of the following members: • Erik Martin, PE, County Manager, FCZD Administrator • Betsy Dillin, PE, Lewis County Department of Public Works—County Project Manager, FCZD Project Manager • Lara McRea,Assistant to the County Manager, FCZD Clerk • Christina Wollman, Perteet—Project Manager/Lead Project Planner • Kirk Holmes, Perteet—Subject Matter Expert • Rob Flaner,Tetra Tech—CFHMP Expert • Carol Baumann,Tetra Tech—Risk Assessment Lead 2.2 Defining the Planning Area The planning area for this Flood Plan is defined as the portion of Lewis County within the Chehalis River Basin, including cities. The Flood Plan assesses the flood risk for all municipalities in the planning area. However, not all municipalities participated in the planning process or identified actions.The planning area is shown in Figure 2-1. 12 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 2-1. Planning Area. ` ey Olympia -1.: . Elk Blain eV lehave�.��2 • South creek T ' ter y7 North Y8 7 Yelm - -— � ��. mot_i`� Py, f � . r4utes Rler .Sra "'creek Sor to - 'Piker t Nill sit, - - \\,. ' L. s.,.?„. Grad ound uRi�" % " 1 4 r - i Centralia ., �f.\ "" - F Chehaliss o , �, ,,t..,,, r: ; lea vine �� CO :- %.� Pe Ell '� �, re �° ..S''outh Fa . itip'►_� Re' '- 4 ? Via, Marl e�l _,� r, ^" - ' ... Legend !t TM . 1411..._ `' -� G 1Q Upper Chehalis Watershed ''. j�, �,�� i' ^i k, �$` CJ I _- ✓ ,r n CM Lewis County Boundary sF 'saint 1=1 Planning Area 00 . LS" 4 8 t ' 1 I I I I ,C•truike-1 ', -, Date:8/21'2021 Miles $ti.j Source:Lewis County:WA Deppt of Ecology.ESRI 2.3 The Stakeholder Committee A Stakeholder Committee was formed to oversee all phases of the planning effort.The members of this committee included key Lewis County staff, citizens, and other stakeholders from within the planning area. The planning team assembled a list of candidates representing interests within the planning area that could have recommendations for the Flood Plan or be impacted by its recommendations.The team confirmed a committee of 11 members and 10 alternates, listed in Table 2-1.The planning team ensured that the committee make up met the requirement for CRS credit.The committee included 10 members representing the County and Cities of Centralia and Chehalis, and 11 members representing the public. Leadership roles and ground rules were established during the Stakeholder Committee's initial meeting on March 24, 2020. Due to COVID-19 quarantine rules, the first few stakeholder meetings were held online.This presented a challenge to the project team and slowed the project. Even though the Stakeholder Committee agreed to meet monthly as needed throughout the course of the plan's 13 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T development,there were some months without stakeholder meetings.The planning team found it was difficult for the committee members to hold the robust discussions necessary for plan development over a virtual meeting, so some meetings were postponed hoping for the ability to meet in-person. Meetings were held in-person as soon as quarantine rules were relaxed, although about half of the stakeholders continued to attend virtually. The planning team facilitated each Stakeholder Committee meeting, which addressed a set of objectives based on an established work plan.The Stakeholder Committee met 7 times from February 2020 through June 2021. Meeting agendas and meeting notes are available for review upon request.The attendance record is listed in Table 2.2.All Stakeholder Committee meetings were open to the public and advertised as such on the FCZD website (see Section 2.6.1).The agendas and meeting notes were posted to the website. Table 2-1.Stakeholder Committee. Name Title Jurisdiction/Agency Tim Fife County Engineer Lewis County Betsy Dillin (A) Project Manager Lewis County Lee Napier Director, Community Development Lewis County Preston Pinkston (A) Planner Lewis County Andy Caldwell Deputy Director, Emergency Management Lewis County Fionna Velazquez (A) Emergency Management Coordinator Lewis County Emil Pierson Director, Community Development City of Centralia Hillary Hoke (A) Planner City of Centralia Celeste Wilder Planner City of Chehalis Tammy Baraconi (A) Director, Community Development City of Chehalis John Henricksen FCZD Advisory Committee Member Chehalis River Basin FCZD Bill Brumsickle FCZD Advisory Committee Member Chehalis River Basin FCZD Bonnie Canaday Coumbs FCZD Advisory Committee Member Chehalis River Basin FCZD Charles Coddington FCZD Advisory Committee Member Chehalis River Basin FCZD Dan Maughan(A) FCZD Advisory Committee Member Chehalis River Basin FCZD Steve Grega (A) FCZD Advisory Committee Member Chehalis River Basin FCZD Dave Muller(A) FCZD Advisory Committee Member Chehalis River Basin FCZD A.Jason Humphrey(A) FCZD Advisory Committee Member Chehalis River Basin FCZD Alex Rosen Floodplain Management Specialist WA Department of Ecology Chrissy Bailey(A) Community Liaison Office of the Chehalis Basin J.Vander Stoep Citizen 14 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Table 2-2.Stakeholder Experience. Natural Structural Stakeholder Preventative Property Resource Emergency Flood Public Measures Protection Services Control Info Protection Projects Lewis County X X X X X X Tim Fife X X X X X Betsy Dillin X X X X X X Andy Caldwell X X X Fionna Velazquez X X X Lee Napier X X X X X X Preston Pinkston X X X X X X City of Centralia X X X X X X Emil Pierson X X X X X X Hillary Hoke X X X X X X City of Chehalis X X X X X X Celeste Wilder X X X X X X Tammy Baraconi X X X X X X Table 2-3.Stakeholder Meeting Attendance Records. Stakeholder #1 #2 #3 #4 #5 #6 #7 Lewis County X X X X X X X Tim Fife X X X X Betsy Dillin (A) X X X X X X X Andy Caldwell X X X X X Fionna Velazquez (A) X X X X X Lee Napier X X Preston Pinkston (A) X City of Centralia Emil Pierson Hillary Hoke (A) City of Chehalis X X X X X X X Celeste Wilder X X X X X X X Tammy Baraconi (A) X X X Members of the Public Bill Brumsickle X X Bonnie Canaday Coumbs X Charles Coddington X X X John Henricksen X X X X X X Steve Grega (A) X Dave Muller(A) A.Jason Humprey (A) Dan Maughan (A) Alex Rosen X X X X X X Chrissy Bailey(A) X X X J.Vander Stoep X X X X X 15 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 2.4 Coordination with Other Agencies Opportunities for involvement in the planning process were provided to neighboring communities, local and regional agencies involved in flood hazard mitigation, agencies with authority to regulate development, businesses, academia, and other private and nonprofit interests (CRS Step 3).This task was accomplished by the planning team as follows: • Stakeholder Committee Involvement—Agency representatives were invited to participate on the Stakeholder Committee. o Washington State Department of Ecology o Office of the Chehalis Basin o Chehalis River Basin Flood Control Zone District o City of Centralia o City of Chehalis • Agency Notification—The following agencies were invited to participate in the Flood Plan development from the beginning and were kept apprised of plan development milestones: o Chehalis River Basin Flood Authority o City of Napavine o Town of Pe El • Pre-Adoption Review—All the agencies listed above were provided an opportunity to review and comment on this Plan, primarily through the Flood Plan website and SEPA review. Each agency was sent an e-mail message informing them the draft Flood Plan was available for review. In addition,the complete draft Plan was sent to the Insurance Services Office, FEMA's CRS contractor,for a pre-adoption review to ensure CRS program compliance. o Washington Department of Natural Resources o Washington State Department of Transportation o Washington Department of Fish and Wildlife o Washington Department of Archaeology and Historic Preservation o United States Army Corps of Engineers o Washington State Department of Agriculture o Washington State Department of Commerce o Cowlitz Indian Tribe o The Confederated Tribes of the Chehalis Basin o Quinalt Indian Nation o Nisqually Indian Tribe o Lower Columbia Fish Recovery Board o Washington State Parks o Puget Sound Regional Council 16 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 2.5 Review of Existing Programs The planning effort included review and incorporation, if appropriate, of existing plans, studies, reports, and technical information. Chapter 4 of this plan provides a review of laws and ordinances in effect within the planning area that can affect mitigation actions, including an assessment of all Lewis County regulatory,technical, and financial capabilities to implement flood hazard mitigation actions. In addition, the following programs can affect mitigation within the planning area: • Lewis County Comprehensive Plan • City of Centralia Comprehensive Plan • City of Chehalis Comprehensive Plan • Lewis County Multi-Jurisdictional Hazard Mitigation Plan (2016) • Chehalis Basin Comprehensive Flood Hazard Management Plan (2009) • Chehalis Basin Strategy • Lewis County Emergency Response Plan • Stormwater Management Manual for Western Washington • Lewis County Critical Areas Ordinance • Lewis County Shoreline Master Program 2.6 Public Outreach Strategy The public outreach strategy originally planned for a combination of in-person and online outreach to ensure the most people possible were able to connect with the project. However,the first public outreach event was planned for mid-April 2020. Due to COVID-19 restrictions, an in-person meeting was not possible, but the online open house was released as scheduled.The second public outreach event occurred during August and September 2021 and included a hybrid in-person and virtual open house and an online open house. 2.6.1 Public Outreach Opportunity#1 The first public outreach opportunity was planned at the beginning of the project. Initially,the planning team planned to hold an open house style meeting on April 10, 2020,that was supported by an online story map to reach a larger audience. However, on March 25, 2020,the State of Washington's "Stay home, stay safe" order went into effect.To not delay the project,the planning team decided to release the story map as an online open house and cancel the public meeting. The project team developed the story map to provide information to the public about the project.The story map included information about the project, a timeline of flooding history in the river basin, survey, and a link to an interactive map meant to gather comments from the public. Ultimately,the interactive map was not a successful outreach method, but the survey received 35 responses and the story map was viewed over 1,200 times between April 2020 and August 2021. The FCZD advertised the website using a county email list of over 800 people including the press and an email list of 183 people from the Chehalis River Basin Flood Authority. It was also posted on the district's website.The story map and survey were left active and regularly received views over the year, providing public outreach during the pandemic quarantine periods and over the extended planning timeline. 17 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 2-2 shows page views of the story map, and Figure 2-3 shows the email release.The full story map pages for the Project Background and Planning Process pages and the survey results are provided in Appendix C. 18 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 2-2. Public Outreach#1—Story Map Pages. Chehalis River Basin Comprehensive Flood Hazard Management Plan Update n v Welcome! Proiecr Background Planning Process Take The Survey, Interactive Timeline A The Chehalis River Basin Flood Control Zone District (FCZD) is updating the Lewis County Comprehensive Flood ,41ta` ""'_-y- - - Hazard Management Plan ...,-_h (CFHMP). .. ` CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT This Story Map has been developed to keep youinformed throughout the process and CHEHALIS RIVER BASIN provide you you an opportunity to participate online in lieu of a public meeting during the " , "Stay Home,Stay Healthy"order. COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN UPDATE The tabs across the top of the page provide you 'j.r information and opportunity to comment and 41.4.. provide feedback.Please take our survey. - During the planning process you will be invited • 'ems, c e# . to attend public meetings and review the draft plan.Meeting dates will be advertised and ; �_�' �..r posted here when they are determined.Leave us your email address below to receive project . 1 ` .. " i.= v updates. i� For more information about the project, I - contact Betsy Dillin at 360-740-1138. R. Chehalis River Basin Comprehensive Flood Hazard Management Plan Update CFF.IT.tdate o r c' Welcome! Project Background Planning Process Take The Survey. Interactive Timeline n t..lei . ► ' „,. f if' 1- . Project Background © . a . v \ 1 ' .. What is a CFHMP? <> 5 4r' ..t.government to document goals and policies for F' iil , �` `i the management of floodplains.The CFHMP I �� 5 i3"S.•, `F• '1. will also identify actions that can be taken to +.- a 1.-_-ST y lc reduce the impacts of flooding from the 1 q ' •v Chehalis River and its tributaries.The CFHMP ..e ^ • " c. ",t .' 1 �. will guide the Chehalis River Basin Flood ' �„ �'p I s , -- Control Zone District(FCZD)administrators, T r . >f! 'i Board of Supervisors,and Advisory Committee a"c. : in FCZD operations.For more information n"'� r ', ,yy r I�-•.�'1r about the FCZD,visit the FCZD wrbsice. =w' ; * '! F'` A+. ♦YiC .t .: Is this project related to the ...i4. 4. foi'�•; i 'fit proposed flood retention facility or _y, , n"4,4'-----F NO1�w airport levee? • ' r am ^.'Y� Not directly.The flood retention facility is part • f.'+i h` , of the Chehalis Basin Strategy.This CFHMP ,r;'1, 1".- ••' _ 1 planning process is also part of the Chehalis Z • '' �� ONO. - Basin Strategy,but is focused on actions that '' > �� " •' '•" ` can be taken by local government to address ••d �•1 - -►` a ' local flooding issues.More information about • h`, ". the flood retention facility can be found on the Ik Chehalis Basin Strategy websiioe. '' -ram t * O 19 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T Chehalis River Basin Comprehensive Flood Hazard Management Plan Update -'.nupdate n>r e Welcome! Background Planning Process Take The Survey! interactive Timeline 4 ,,rr Yy � . Planning Process t 11,075, f The planning team is following a 10-step �p! SOUTH planning process.Each step is described below. �� H 's / V I law?all, Step 1:Organize + a +• • A stakeholder committee was formed to guide : ' the planning process.The committee includes - representatives from Lewis County,the cities of '. Centralia and Chehalis,Department of Ecology, - . and interested citizens.The committee ? ry'«ir` generally meets on the 4th Tuesday of each month.For exact meeting dates and locations,agendas,and meeting summaries,visit the :� 't'FCZD website.All stakeholder meetings are n `open to the public. ,t 1Step 2:Involve the public ��_Public participation is vital for the success of �� 111K111111, this project.There will be at least two public - f ` ---_- meetings during the process,the draft CFHMP _ will go through a public review and comment period,and the final plan will be adopted after - -- r .. ' holding a public hearing. - -- — Int Step 3:Coordinate '_; • t The Chehalis basin has been studied for years by local,state,and federal agencies.Significant infnm+atinn alrnarlw evicrc rn h.ln i is ..�- r+'•yk• Chehalis River Basin Comprehensive Flood Hazard Management Plan Update CFHMP Update n e/a' MN Welcome! Project Background Planning Process Take The Survey! Interactive Timeline We want to hear from you! You can also take our survey at this link _.._..___....er Basin Comprehensive Flood Hazard Management Plan 1.Where in Lewis County Co you live? Chehalis r)Unincorporated Lewis County within Chehalis River Basin '7,Centralia ._)Outside of the Chehalis River Basin,including_ _)Pe Eli Cowlitz River Basin(W inlock,Toledo,Vader, Packwood,Morton,Mossyrock,etc),Deschutes _)Napavine River Basin,or Nispually River Basin �;)l do not live in Lewis County (,)Other(please specify) 2 Do you work in Lewis County? Yes No 20 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T Chehalis River Basin Comprehensive Flood Hazard Management Plan Update CFHMPUpdate fi IF a Welcome! Project Background Planning Process Take The Surrey., Interactive Timeline To,new the timeline in a separate window,visit this Fide. '111 ';° RICAL FLOODING IN -- r ' S COUNTY FROM 188 - f:� -�.: PRESENT DAY � yy. y 'ter,a " . (ZL Floudingisa=norconcernin Lewis County.Flood emitshaaausedmullionsof ,4' '+�'.F, dollars in damage,lost commerce,and disrupted lives.Recent events and the le f.p.� w .,. , - formationof the Clithalis River Eosin Flood Control Zone District(FC2D have ;L, --»...- t try r 0, CM:trey the caryto update the CamprehetshveflaodHa;zrdNEtigationPlan; .1 ... -.Gl, 1 Pspartafthisprocess,leislmoortanttorernpiethehistmTcalconteuoffioodingin '. . the regson.This timeline includes historical flood information and hisrxical river crests 3 ` . as ofFebruary21,2020.Therindiatesthat$and'shistorical.ranlcTheChehalisFi Fiver ., and S1s oGumrltuckRr=et crests are from the gages in Centralia.The Cendia!liver s+'�1:7- crests are from the gage in Pack-.wad. ' information from the Daily Chronicle article From Native American Legends to 2007:A, -` N i History.•Flood r eh•in the• alis f ivv rAasin and National Weather Snrrvice ',r 21 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 2-3. Public Outreach#1—Email Release. Christina Wollman From: Lard McRea Clara Mcaeaiwlewrscounrywa.gov• Sent: Friday.April IC,2020 10:21 AM Subject: Comprehensive Flood Hazard Management Plan Update c%:,,,slito CO,.tpoc ze+e,c nrarmcr CHEHALIS RIVER BASIN • � ,.', +IflasmE FLOOD HAZARD MANAGEMENT EL AV fir'DATE THE CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT IS UPDATING THEIR COMPREHENSIVE FLOOD PLAN The Chehalis River Basin Flood Control Zone Drslncl;FCZD)is currently updating the Lewis County Comprehensive Flows Hazard Management Plan(CFMJPi.Thu update is bang led by Betsy Drain from Lewis County Public Works and guided by a group of Stakehoders comprised of representatives from Levers County the r of Chehalis and Centralia.Department of Ecology.FCZD Advisory Commdtee and the pudic. A CFHMP prov,des an overall strategy of programs,projects,and measures aimed at reducing the adverse impacts of flood hazards on the community.The plan will coordinate and support the activates occumng within the Chehalis River Basin and provide guidenco for FC7D prolects and achvities within Lewis County The project is funded by a grant from the Chehalis River Basin Flood Authority end will be completed by June 30,2021 A Story Map has been developed to keep you informed throughout the process and provide you an opportunity to partaupale triune in lieu of a pudic meeting during the'Stay Home,Stay Heakny order. The tabs across the top of the webpage provide you information and opportunity to comment and provide feedback. Please take oo-x survey and show us areas of concern of our interactive map. During the planning process you will be Trailed to attend public meetings and review the draft plan. Meeting dates will be advertised and posted when they are determined CFHUP webalb address: Fcr question!, feel"t`n' t 'b'din at 360-740-1138 Clkk here Our mailing address is: 351 NW North St Chehalis,WA 98532 360 740 1138 22 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 2-4. FCZD Website. CHEHALIS RIVER BASIN FLOOD HOME ABOUT NEWS QUICK LINKS EIS AND SUPPORTING DOCUMENTS CONTACT CONTROL ZONE DISTRICT Comprehensive Flood Hazard Management Plan Update (CFHMP) A CFHMP provides an overall strategy of programs,projects,and measures aimed at reducing the adverse impacts of flood hazards on the community.The plan will coordinate and support the activities of the Office of the Chehalis Basin,and provide guidance for FCZD projects and activities within Lewis County. Previous CFHMP-2009 Lewis County Comprehensive Flood Hazard Management Plan Meeting dates,Agendas,Meeting Minutes Interactive Plan Website 0 2.6.2 Public Outreach Opportunity#2 The second public outreach opportunity occurred during the draft plan review period. On August 24, 2021,the Planning Team sent out a press release (Figure 2-5)to notify the public that the draft plan is available for review and there will be an open house on September 1, 2021.The Planning Team also sent an email to the county's email notification list with 1200 subscribers and updated the project website (Figure 2-6). Because COVID-19 meeting restrictions were still in place,the Planning Team prepared a hybrid meeting to allow participants to choose to attend either in person or online through Zoom. Six people attended in person and nine online,for a total of fifteen attendees. During the meeting, the Planning Team gave a short presentation and then had discussion while reviewing large, printed maps.The Planning Team also prepared a map station to provide attendees a map of their property with the different floodplains overlaid (Figure 2-7).All virtual attendees received PDFs of the meeting materials. All meeting materials are provided in Appendix C. Prior to the August 24, 2021, press release,the Planning Team updated the story map.The updated page views are shown in Figure 2-8, with full pages provided in Appendix C. 23 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 2-5. Public Outreach#2—Press Releases. Chehalis River Basin 444 . Flood Control Zone District 351 NW North St Erik P.Martin.P.F.,District.Administrator Chehalis,WA 98532-1900 NOTICE OF OPEN HOUSE CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT NOTICE is hereby given that the Chehalis River Basin Flood Control Zone District Supervisors will host an open house for the public to learn more about the draft Chehalis River Basin Comprehensive Flood Hazard Management Plan.This open house will be both in-person and online using Zoom. WHEN: Wednesday,September 1,2021 TIME: 5:30 p.m.—6:30 p.m. WHERE: Lewis County Commissioners Hearing Room,second floor 351 N.W. North Street,Chehalis WA 98532 The Comprehensive Flood Hazard Management Plan(CFHMP)is focused on the portion of Lewis County within the Chehalis River Basin.The goal of the plan is to minimize the long- term risk to life and property from flooding.The CFHMP evaluates the risk and vulnerability to flooding and identifies mitigation actions the community can take to reduce the impacts of flooding. It also includes goals,objectives, and policies to support the local agencies when making decisions related to flooding. For the past two years, a stakeholder committee of local officials and citizens have been meeting to develop the plan.The committee is ready to present to the plan to the public for review and comment.The public comment period ends on September 30,2021. During the open house,the project team will provide an overview of the planning process, the results of the risk assessment,and the proposed mitigation actions. If you are unable to attend the open house,you can visit our interactive website to learn more about the plan and provide comments. You can download the plan and find out more information at: https://www.chehalisriverbasinfczd.com/cfhmp. Please submit comments on the draft CFHMP by September 30,2021 using the comment form on the project website or by emailing the Project Manager,Betsy Dillin. Contact Betsy for more information at 360-740-1138 or by emailing Betsy.Dillinalewiscountywa.gov. DATED this 24th day of August 2021. 060 Lara McRea,Interim erk of the Board Notice sent to media: August 24,2021 24 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 2-6. Updated FCZD Website. CHEHALIS RIVER BASIN FLOOD HOME ABOUT NEWS QUICK LINKS EIS AND SUPPORTING DOCUMENTS CONTROL ZONE DISTRICT Comprehensive Flood Hazard Management Plan Update (CFHMP) Save the Date CFHMP Open House-Wednesday,September 1,2021 Press release CFHMP INTERACTIVE PLAN WEBSITE Chehalis River Basin Comprehensive Flood Hazard Management Plan-DRAFT CFHMP Appendices-DRAFT Display Maps Action Table Figure 2-7. Map Station Example. Lewis County Courthouse / , • %� ih t I„ iro' ��. 1 i. eA 10 252C21.11.21 C5 AM 1.1614 14 Wort Transpnrtaton- .P'anelnq Arse'N3rcoursss MI ModeletllGSVear Flootlplan Pa ala t=1 Lewu Cuunt';Bounn:uv Modeled la0-Yeaw Cl-ale Change Flonsein Cnes Elective'a Yet Floenpain IFEMAI U " 25 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 2-8. Public Outreach#2—Story Map Pages. Chehalis River Basin Comprehensive Flood Hazard Management Plan Update CFHMP Update n it CP Welcome! Proposed Mitigation Actions Submit Your Comments, Project Background Planning Process Interactive Timeline .K:..,,y. Chehalis River Basin - , Comprehensive Flood Hazard Management Plan :, '`1' " v. ' slik • t „ Chehalis River Basin Flood ,. tin!Zone District 1 , .. ; :, -p` ----""' - / f"` ram' ~r5 Chehalis River Basin Comprehensive Flood Hazard Management Plan Update CRAW 141date [a fI e2 Ian Welcome! Proposed Mitigation Actions Submit Your Comments, Project Background Planning Process Interactive We w .l - 61 Proposed a Mitigation Actions . Chehalis River Basin ".` . . Comprehensive Flood Hazard i, y Management Plan •N spy, 26 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Chehalis River Basin Comprehensive Flood Hazard Management Plan Update ri sr L? Welcome, Proposed Mitigation Actions Submit Your Comments! Project Background Planning Process interactive Timeline m Chehalis River Basin CFHMP 1`. Use this form to submit comments on the draft CFHMP.You can also email your comments to "" "' Betsy Dillin at Betsy.DillineFewiscountvwa.gou. APIIIIIP. Akr ,..e.'''''. Review Comments Nile- - Please provide your name and contact information.0 Al Name* -vd .014 ter. Email(optional) NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 2.7 Plan Development Chronology/Milestones Table 2-4. Plan Development Milestones. Date Event Description 2-25-2020 Kickoff Meeting The project team introduced themselves to the planning partners.The County provided background on the project.The project team described the planning process. 3-24-2020 Stakeholder Meeting#1 • Stakeholder Committee organization • Past and current plan review • Critical facilities definition • Review Hazus risk assessment • Discuss public outreach plan 4-10-2021 Public Outreach#1 • Online Open House (story map) • Survey 4-28-2020 Stakeholder Meeting#2 • Risk assessment update • Confirm goals and objectives • Introduce capability assessment and SWOO • Public outreach update 6-23-2020 Stakeholder Meeting#3 • Risk assessment update • Capability assessment and SWOO • Introduce policy discussion • Public outreach update 7-21-2020 Stakeholder Meeting#4 • Policy discussion • Introduce action plan process 11-17-2020 Stakeholder Meeting#5 • Policy discussion • Introduce plan maintenance strategy 1-12-2021 Action Development • Discussed actions Workshop • Provided 3-16-2021 Stakeholder Meeting#6 • Confirmed plan maintenance strategy • Reviewed policies • Discussed actions 5-18-2021 Planning Team Meeting • Discussed draft plan review process and public involvement plan. 6-30-2021 Stakeholder Meeting#7 • Reviewed draft plan • Discussed public outreach and plan comment and adoption process 8-24-2021 Public Comment Period • Begin public comment period • Comments accepted from August 24, -2021 to September 30, 2021 28 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Date Event Description 9-1-2021 Public Meeting#2 • Hybrid open house held in-person and online 9-30-2021 SEPA DNS Comment Period • Comments accepted through October 13, 2021 11-22-2021 City of Centralia Public • Centralia City Council public hearing prior and Hearing and Adoption plan adoption 11-30-2021 Public Hearing and • Joint public hearing with the Lewis County Adoption Commissioners and FCZD Board of Supervisors. • Adopted by Lewis County and by the FCZD 29 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 3.0 LEWIS COUNTY PROFILE Lewis County is located in Western Washington along the I-5 corridor to the south of Puget Sound.The County stretches from the Willapa Hills in the west,though the Chehalis River basin, and east into the Cascade Mountain Ranges encompassing portions of both Mt. Rainier National Park and Mt. St. Helens National Monument.This plan focuses on the Chehalis River basin in the western portion of the County, though portions of the profile are focused county-wide. 3.1 Historical Overview This section on the historical overview includes excerpts from the Lewis County Shoreline Inventory and Characterization Report(ICR) (Herrera, 2013). 3.1.1 Native Americans (ICR Section 3.6.1, Herrera, 2013) Native peoples that historically inhabited the area now within Lewis County were primarily the Upper Chehalis and Cowlitz Tribes of the Southwestern Coast Salish (Hajda 1990).The Meshal and Nisqually Tribes,which lived in the northeastern part of present-day Lewis County,were Southern Coast Salish (Suttles and Lane 1990).The Suwal Tribe of the Kwalhioqua people lived in the western part of the County;they shared territory with the Cowlitz and Upper Chehalis Tribes (Krauss 1990). Salmon was a significant food source for all these tribes.Tribe members also gathered nuts, berries, and tubers from the forest and prairies. Most villages were located at the mouths of rivers and creeks. In general, native people lived near fishing streams in cedar longhouses during the winter months (Chehalis Tribe 2009; Irwin 2011). In spring,they would move to prairies to dig camas and wapato. Some of the tribes would move to higher ground in summer and fall to harvest berries and hunt game. The Upper Chehalis lived along the banks of the Chehalis River (Wilma 2008; Chehalis Tribe 2008).They were expert fishers and paddlers of shallow shovelnose canoes. In addition to salmon,their primary staple,they harvested steelhead, eels, freshwater clams, and crayfish.They also used the Chehalis and Cowlitz River systems as trading routes, and they traded among the several bands of both Upper and Lower Chehalis Tribes, as well as with other peoples(U-S-History.com, undated). The Cowlitz people inhabited an area south of the Cowlitz River—and south of the Upper Chehalis, Meshal, and Nisqually people (Irwin 2011).The Cowlitz people are divided into two main groups:the Upper Cowlitz and Lower Cowlitz.The Upper Cowlitz occupied villages east of present-day Mossyrock and camped at higher elevations in the Cascades.They were known for their hunting expertise (Irwin 2011).The more populous Lower Cowlitz occupied numerous villages along the Cowlitz River from Mossyrock southward to within one or two miles of the Columbia River.The Cowlitz were horse people and, like other peoples in the region, they used trails and rivers (canoes)to visit and trade with other tribes. The Meshal people lived near the Chehalis River headwaters in the Cascade Range. Having horses, they often traded with tribes east of the mountains (Wilma 2008). According to legend, the Nisqually people came north from the Great Basin, crossed the Cascades, and settled their first village in the Skate Creek basin (within the Cowlitz River watershed),just south of the 30 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Mashel River watershed (Nisqually Indian Tribe 2010). Later,they settled near the Mashel River.Their lands extended to Puget Sound. Salmon and fishing are culturally significant, and salmon remains the mainstay of their diet (Nisqually Indian Tribe 2010). Little has been recorded about the Suwal (Kwalhioqua) (Krauss 1990).They hunted game, gathered berries and roots, and also fished.Their relations with other tribes and Europeans "were beset with conflict" (Krauss 1990). By the mid-1850s, most of the Kwalhioqua had disappeared. 3.1.2 Euro-American Settlement (ICR Section 3.6.2, Herrera, 2013) Between 1818 and 1846,the United States and Great Britain jointly occupied the Pacific Northwest.The Hudson's Bay Company established trading posts at Fort Nisqually on Puget Sound and at Fort Vancouver on the Columbia River. By the early 1800s, Hudson's Bay Company traders were using the Cowlitz Trail to travel between Fort Vancouver and Fort Nisqually(Wilma 2008).The Cowlitz Trail was originally a Native American portage between the Chehalis and Cowlitz Rivers (Wilma 2008) and had been used for hundreds of years as part of the natives'trading routes (Tumwater 2005). In 1845,the first European settlers traveled from Fort Vancouver to the mouth of the Deschutes River near present- day Tumwater,Washington (Tumwater 2005).To do so,they built a wagon road along the Cowlitz Trail, beginning at Cowlitz Landing, near present-day Toledo (Yakima Valley Historical Society, undated). Today, most of the Cowlitz Trail has disappeared due to road construction and other human activities (Tumwater 2005). In Lewis County, communities with good water access developed first. By the 1850s,there was a small settlement at Cowlitz Landing that catered to settlers traveling north to Puget Sound (Tumwater 2005). In the 1860s, Cowlitz Landing had a store, a hotel,a post office (first post office in the county),and several other buildings. Because of the dynamic nature of the Cowlitz River,which has altered its course so much during the past 150 years, no trace of Cowlitz Landing remains. In 1851, Stuart Schuyler Saunders settled near the Chehalis River at what would become Saundersville; and then, in 1872, renamed Chehalis (Winlock 2008, Wall 2008, and Chehalis 2013). Chehalis became the county seat in 1873, shortly after the Northern Pacific Railroad was built from Kalama, on the Columbia River, through Chehalis.The railroad extended from Kalama, on the Columbia River,to the Chehalis River in 1872 and on to Tacoma in 1873 that same year.The first town center was on West Main Street, near the railroad.The town center shifted down West Main Street to the corner of Chehalis Avenue and West Main;that second town center was destroyed by fires in 1892 (Chehalis 2013).The third city center was built along Market Boulevard and is the city's present historic downtown central business district (Chehalis 2013). In 1875, after having lived in the area since 1851,African American George Washington filed a plat on a town he called Centerville.The town was on the Northern Pacific Railroad line at the confluence of the Chehalis and Skookumchuck Rivers (Ott 2008).The town was renamed Centralia in 1883 (Ott 2008) and was incorporated as Centralia in 1886 (Wilma 2008). The first two settlers in Winlock, C.C. Pagget and Jacky Nealy, arrived in 1871 (Wall 1952).They acquired land on both sides of the railroad line (which was not yet built) in the town's present location.The town was founded in 1873 (Wall 1952). 31 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Morton was first settled by James Fletcher in 1871. It was named Morton in 1889 and was incorporated in 1913 (Wikipedia 2013). In the 1950s, the world's longest railroad tie dock ran along the railroad tracks east of Morton (Sparkman 1994), and the town was known as the "tie mill capital of the world" (Wikipedia 2013). By 1883,the towns in Lewis County included Centralia, Chehalis, Morton, Mossyrock, Napavine, Pe Ell, Toledo,Vader, and Winlock. In the 1880s,the US Army Corps of Engineers cleared snags from the Chehalis River,which allowed steamers to travel from Grays Harbor as far upstream as the railroad connection at Chehalis (Wilma 2008).The river dredging and railroad made it possible to exploit the county's timber resource. Lumbering became the principal industry in Lewis County, attracting new immigrants to the region (Wilma 2008).Although the US government preserved large tracts from settlement in 1897 (later the Gifford Pinchot National Forest),timber could be cut on those lands. Logging and milling operations attracted thousands of workers in the early 1900s.The timber industry dropped off in the 1920s, followed by the Great Depression in the 1930s.The county economy rebounded in the 1940s as World War II increased demand for wood and agricultural products (Wilma 2008). 3.1.3 Historic Uses of the River and Floodplain The logging and agricultural industry had a great effect on the river and its floodplains. For decades, snags, log jams, and other obstructions were removed from the riverbed and wetland and riparian areas were cleared along the riverbanks to create more room for agricultural uses and land development as the population increased. The logging industry used splash dams from the 1880s to the 1920s within the main stems of the Chehalis River and South Fork Chehalis River, and tributaries including Elk Creek, Hope Creek, Deep Creek, and the Skookumchuck River. Splash dams were temporary dams constructed to store water and harvested logs. When the splash dam was destroyed,flood waters quickly transported the logs downstream.The fast-flowing influx of logs scoured the riverbed, removing all sediment and gravel. Remnants of the splash dams remained in place until the 1940, when they were removed. Splash dams and obstruction removal significantly simplified the river system and the effects are still felt today.The river has not been able to reclaim the diversity and complexity that existed prior to settlement(Army Corps of Engineers, 2002). 3.2 Physical Setting Lewis County is bounded on the east by the crest of the Cascade Mountain Range and extends west to the Willapa and Doty Hills.The County crosses three physiographic provinces:the Cascade Range,the Puget-Willamette Lowlands, and the Pacific Coast Range.The Chehalis River valley occupies most of the western parts of the County, and the Cowlitz River valley occupies most of the central and eastern parts. A small portion of the mountainous north central part of the County contains the Nisqually and Deschutes watersheds. The uplands of the eastern County are composed of rugged mountainous and alpine topography, modified by glacial activity, and drained by rivers that flow generally westward.The landscape is characterized by long, steep slopes and relatively straight, parallel drainages. Ridge tops have an average elevation of approximately 4,000 feet. 32 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 3.2.1 Watersheds The County includes watersheds associated with four major rivers:the Chehalis River, Cowlitz River, Deschutes River, and Nisqually River.This plan is focusing on the Chehalis watershed, which encompasses the western portion of the county, including the Cities of Centralia, Chehalis, and Napavine and Town of Pe El.The Chehalis watershed is the most vulnerable watershed in the County. Not only does it flood with the greatest frequency, it is also the county's population center with significant residential, commercial, and industrial development located within the expansive floodplain. WRIA 23— Upper Chehalis Basin Chehalis River The Chehalis River originates in the Cascade foothills surrounding the Cities of Centralia and Chehalis, and eventually flows into Grays Harbor at Aberdeen.The river basin, located at the southern end of the Puget Trough, has a total drainage area, including tributaries, of approximately 2,114 square-miles.The valley is characterized by a broad,well-developed floodplain, and low terraces surrounded by highly dissected uplands of low to moderate relief, that have broad, rounded ridges. Many perennial streams drain these ridges. Elevations within the basin range from 170 feet at Chehalis to over 5,000 feet at the headwaters. Most uplands in the basin average 300 to 600 feet in elevation.A low divide occurs between the Chehalis River basin and the Cowlitz watershed to the south a few miles south of Chehalis, between the communities of Napavine and Winlock. At their closest point,the Chehalis and Cowlitz Rivers,the two largest rivers in southwestern Washington, are only 16 miles apart. The Chehalis River valley is characterized by the Willapa Hills in the west and by the Cascade foothills in the east,with broad, developed floodplains downstream of its confluence with the south fork of the Chehalis River.The river gradient from its source to the floodplain is steep with an average gradient of 16 feet per mile.The Chehalis River uplands are undergoing tectonic uplifting. This lowering and lifting of the Chehalis River valley changes the gradients of streams and other waterbodies.The tectonic action, along with the heavier precipitation and sedimentary rock in the Chehalis-Centralia floodplain, generates bed load material that must be moved from the river channel. Sedimentary rock is usually weaker and easier to erode, and this process is hastened by high peak flows.A river channel with a low gradient tends to form meanders as a way to remove heavy bed material.The change in channel gradient from tectonic activity can compound this meandering action. The Chehalis River, in the Centralia-Chehalis valley, has a meandering channel that occupies a uniform floodplain averaging over one mile wide. Most of the valley is inundated during a severe flood such as the January 1990 flood.Tributaries to the Chehalis River in the Chehalis-Centralia valley include Dillenbaugh Creek, Newaukum River, Salzer Creek, Coal Creek, China Creek, Skookumchuck River, and Coffee Creek(Lewis County, 2008). Skookumchuck River The Skookumchuck River, one of the major Chehalis River tributaries,joins the Chehalis River, and is approximately 41 miles in length. It originates in the Mt. Baker-Snoqualmie National Forest northeast of the City of Centralia and empties into the Chehalis River at Centralia.The total drainage area for the Skookumchuck River is 181 square miles. Elevations within the basin range from 150 feet at the mouth to 3,800 feet at the headwaters,with approximately two-thirds of the basin located below an elevation of 1,000 feet.The slope of the Skookumchuck River from its source to the town of Bucoda is steep, 33 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T falling an average of 19 feet per mile. Below Bucoda,the slope flattens to about five feet per mile near Centralia. Except for the uppermost portion,the Skookumchuck River flows as a meandering channel in a floodplain,varying in width from a few hundred feet to 0.5 mile. Three developments are notable within the Skookumchuck River system.The first is the City of Centralia,which occupies several square miles at the lower end of the basin.The second development is Skookumchuck Dam, located about 20 miles upstream from Centralia and operated by PacifiCorp. Skookumchuck Dam was completed in 1971 and has been considered several times for flood control use.The third development of note in the Skookumchuck Basin is the Centralia Steam Generating Plant on Hanaford Creek.Authority has been granted for this coal-fired facility to divert up to 54 cubic feet per second (cfs) of water from the Skookumchuck River. The Skookumchuck River is regulated by the Skookumchuck Dam,which is owned by Scottish Power (PacifiCorp). Skookumchuck Dam is located at RM 21.9,just upstream from Bloody Run Creek.The dam is an earthfill structure approximately 190 feet high with a crest elevation of 497 feet. Construction of the dam was completed in January 1971.The primary purpose of the project is water supply for the Centralia coal-fired power generator plant. Outflow from the reservoir is either over the spillway crest at elevation 477 feet or through the outlet works with intake gates at elevations 449,420, and 378 feet. The discharge capacity of the outlet works is approximately 220 cfs when the pool elevation is at the spillway invert. Because of this limited outlet capacity,the reservoir typically fills early in the flood control season and passes subsequent floods over the 28,000 cfs capacity spillway.The normal active storage capacity of the reservoir is 38,700 acre-feet (ac-ft) between elevations 400 feet(normal minimum operating pool) and 492 feet (maximum operating pool).Additional usable storage of 3,170 ac-ft is available between elevations 378 feet(invert of the lowest intake) and 400 feet. Dead storage is approximately 1,420 ac-ft between elevations 378 and 340 feet.The land use in the Skookumchuck River floodplain is generally agricultural in the upper reaches with increasing urbanization towards the mouth.The most developed portion of the floodplain is from the mouth to RM 4.5 with the City of Centralia's central residential/business district being within the floodplain on the left bank near RM 2.0 (City of Centralia, 2008). Newaukum River The Newaukum River is the second major tributary to the Chehalis River in Lewis County.The Newaukum River's headwaters are in the Cascade foothills southeast of the City of Chehalis. At the USGS gauge near Chehalis,where it flows into the Chehalis River,the Newaukum River has a drainage area of 155 square-miles. Elevations in the Newaukum River basin range from approximately 180 feet near the confluence with the Chehalis River to 3,200 feet in the upper basin.The Newaukum River is made up of three forks,the north, middle, and south forks. Upstream sections on both the north and middle forks, above the community of Forest, have slopes of 83 feet per mile;the south fork has a slope of 188 feet per mile above Onalaska.The average channel slope for the entire drainage is 35 feet per mile. Dillenbaugh Creek Dillenbaugh Creek flows into the Chehalis River,from the east at Chehalis. It originates in the steep foothills southeast of Chehalis and has a drainage area of approximately 15 square-miles.The gradient of Dillenbaugh Creek in the upper reaches is approximately 70 feet per mile.After it flows out onto the Newaukum River floodplain,the gradient drops as Dillenbaugh Creek parallels the Newaukum and Chehalis Rivers for nearly three miles before finally flowing into the Chehalis River. Dillenbaugh Creek collects much of the City of Chehalis' storm drainage in the lower reach. 34 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Salzer Creek Salzer Creek flows into the Chehalis River from the east just south of the Centralia city limits and drains 24.5 square-miles.The basin originates in the low-lying hills east of Centralia-Chehalis and has a maximum elevation of about 800 feet.The stream gradient of Salzer Creek is relatively flat. Coal Creek, a major tributary of Salzer Creek, has a drainage area of 6.4 square-miles and has a steeper slope (Lewis County, 2008). China Creek China Creek is a relatively small, short stream that flows through the City of Centralia to the Chehalis River.The watershed extends about five miles east of the Chehalis River at Centralia. It encompasses approximately 4.4 square miles, ranging in elevation from 180 feet to 570 feet. Much of the land is moderately steep. Most of the channel consists of pipes and box culverts through Centralia. China Creek is utilized as part of the City's stormwater drainage system. Coffee Creek Coffee Creek is a tributary of the Skookumchuck River. With headwaters in Thurston County, Coffee Creek flows south through the Zenkner Valley to the Skookumchuck River north of Centralia.The watershed encompasses 6.2 square miles of moderately sloping hills. Watershed elevations range from 186 feet at the confluence with the Skookumchuck River to 645 feet at the northern tip of the watershed.The stream gradient is low in the lower four miles of the watershed. Coffee Creek has been moved from its natural location to a periphery channel bordering the edge of adjacent hills and the valley floor. Coal Creek Coal Creek is a small tributary of Salzer Creek that flows west and northwest for approximately 20.5 miles.The drainage area is 6.4 square-miles,with steep channel slopes east of 1-5. Lincoln Creek Lincoln Creek flows into the Chehalis River just north of the City of Galvin. Lincoln Creek originates in the hills west of Centralia gathering water from Cooks Hill and Doty Hills.The gradient of Lincoln Creek is relatively flat winding through the Lincoln Creek Valley (City of Centralia, 2008). 3.2.2 Geology The geology of Lewis County is composed primarily of igneous and sedimentary bedrock of the Tertiary Period, and unconsolidated glacial sediments of the Pleistocene Epoch. After formation of the bedrock, between 7 and 55 million years ago,the surface of the area underwent geologic uplift, raising the volcanic and sedimentary rocks above sea level. Deformation, in the form of faulting and folding, accompanied the uplift. Landslides and erosion followed in the western part of the County; glaciation, glaciofluvial deposition, erosion, and recent volcanic activity followed in the eastern half of the County. Bedrock Geology The oldest rocks in Lewis County are the basalt and basaltic breccia flows of the Doty Hills, in the western part of the County.The flows consist of augite basalt that is generally structureless, although pillow and columnar structures are commonly observed.This rock is of middle to late Eocene age, or about 40 to 55 million years old. It is submarine in origin, having poured out from fissures in the ocean floor. 35 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Much of the area west of the Cascades was covered by the ocean and had a shallow,fluctuating coastline during the late Eocene and Oligocene Epochs (27 to 40 million years ago). Alluvial sand and silt of the eroding, older Cascade area mountains were being deposited into this shallow water.These alluvial deposits were compressed and hardened over time and became sedimentary rock. Closer to the older Cascade core,the sediment, in some areas, was deposited in freshwater, and is characterized by thin beds of carbonaceous shale and coal, such as those in Hanaford Creek and along the Tilton River, north of Morton. As the erosion of the older part of the Cascades was occurring during the middle to late Eocene and into the Oligocene, new volcanic eruptions were emitting flows of molten rock that would eventually rebuild the foothills and mountains of the present-day Cascades.The most prominent flows occurred during the late Eocene and are composed of extrusive basic igneous rock, mainly andesite, andesitic volcanic breccia, and, to a lesser extent, basalt. Slightly older, nonmarine siltstone and sandstone are interbedded with the volcanos in a few areas. Massive volcanic flows continued throughout the Oligocene and into the Miocene, depositing andesite and andesitic breccia that are in evidence today in the mountainous areas north of Randle. Dikes of acid igneous rock, primarily diorite,granodiorite, quartz monzonite, and some granite, later penetrated the existing geologic formations in the eastern part of Lewis County.These structures are common in the southeastern corner of the County, at Tumwater Mountain and Vanson Peak. Erosion from the Cascades during the Miocene Epoch (7 to 27 million years ago) deposited alluvium in broad, shallow basins of stagnant water.This material was eventually consolidated and became the very soft, or weak, siltstone bedrock found in the Wilkes Hills, southeast of Toledo.The siltstone is characterized by interbedded coal, preserved organic matter, and leaf impressions. Glacial Geology The Pleistocene Epoch (2 million to 10,000 years ago) in Lewis County was marked by several episodes of erosion and sculpting of existing landforms, and deposition of glaciofluvial sand and gravel, and glacial till.The oldest glacial sediments in Lewis County are the glaciofluvial deposits of the Logan Hill Formation.The Logan Hill Formation is composed of highly weathered sand, gravel, silt,and clay, approximately one million years old, derived from the Tertiary rocks of the Cascades.The outwash was deposited from the massive glacier, flowing westward from the crest of the Cascades, that carved out the Cowlitz and Tilton River valley troughs. Streams flowing from the melting glacial ice transported, sorted, and deposited the material in a fan shaped, broad plain at the front of the foothills.The extent or perimeter of this plain is roughly defined by the communities of Salkum (east), Chehalis(northwest), Napavine and Winlock (west), and Vader(southwest). Younger glacial till deposits of the Hayden Creek Formation make up the terraces or plains of the upper Nisqually River valley.These deposits are the result of glaciation of the upper Nisqually.Till and outwash of the Hayden Creek Formation also occupy the large U-shaped valley of the Cowlitz River and its tributaries, and the surrounding glacially smoothed uplands.These deposits are visible in roadcuts between Salkum and Morton on US Highway 12 and between Onalaska and Morton on State Highway 508.Typically,they are covered by a thick layer of highly weathered volcanic ash.This ash was apparently aerially deposited on the ice of the valley glaciers during the late Pleistocene,then later laid down like a blanket over the underlying till and outwash when the ice receded. Small cirque glaciers developed in the Cascades during the late Pleistocene at elevations above 2,500 feet.These glaciers formed primarily on the north slopes of ridges and extended down drainages to the 36 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T north and northeast, sculpting out bow shaped cirques, hanging valleys, rocky ridgecrests, aretes, and U- shaped valleys.Thin till deposits from this event remain near the heads of alpine drainages and adjacent side slopes. Ice recessional sand and gravel were deposited near the end of the Pleistocene (approximately 12,000 years ago) as ice was making its final retreat. Coarse glacial outwash was deposited as terraces in both the Cowlitz and Nisqually River valleys.The outwash deposits in these two valleys were derived from glaciers occupying them. Coarse outwash sand and gravel were also deposited in the Chehalis River valley at and surrounding the City of Centralia.These deposits were derived from the Puget Lobe of the Cordilleran Ice Sheet,which originated in British Columbia, covered all the Puget Lowland, and terminated just north of Lewis County. As the ice sheet receded, meltwater,flowing from the ice,filled part of the Chehalis River Valley with clean quartzitic sand and hard, rounded pebbles, cobbles, and stones. In addition to the dramatic eruptions of Mt. St. Helens during the 1980s, Lewis County has experienced many eruptions of Cascade volcanoes. Mazama ash,from the 6,600-year-old event that resulted in the formation of Crater Lake in southern Oregon, can be found in most upland soils in the western part of the County.Ash layers from Mount Rainier and numerous Mt. St. Helens eruptions, in addition to Mazama ash, are present in upland soils of the central and eastern parts of the County. The dominant geologic process that has operated within the last 10,000 years in Lewis County is erosion. Erosion of bedrock, glacial, and tephra deposits has resulted in the deposition of alluvium in the valley or lowland areas of Lewis County.Along the Nisqually River and in the Cowlitz River valley,the alluvium is derived primarily from coarse-textured glacial outwash,volcanic ash, and pumice.As a result,the alluvium in those valleys is coarse and non-cohesive in nature. Fresh alluvium is deposited adjacent to the Cowlitz and Nisqua►ly Rivers by seasonal floods.The Chehalis River and its tributaries drain dominantly older, rounded, lower relief hills of the west half of the County.These hills—composed of softer, more highly weathered, and finer-grained rock—supply alluvium to the Chehalis River that is finer in texture than that of the Nisqually and Cowlitz River valleys (Lewis County, 2008). 3.2.3 Climate The Lewis County Chehalis River Basin area has a predominately marine climate characterized by mild temperatures both summer and winter. Extreme temperatures are unusual for the area because prevailing westerly winds bring maritime air over the basin and provide a moderating influence throughout the year. During the spring and summer, high-pressure centers predominate over the northeastern Pacific, sending a northwesterly flow of dry,warm air over the basin.The dry season extends from late spring to midsummer, with precipitation frequently limited to a few light showers. Average summer temperatures are in the 70s or 80s (degrees Fahrenheit), but occasionally hot, dry easterly winds cross the Cascade Mountains and raise daytime temperatures into the 90s.The Aleutian low-pressure center normally predominates during the winter, causing a counterclockwise circulation of cool, moist air over the basin and prevailing southwesterly winds.The area from the Pacific Ocean to the crest of the Olympic Mountains,the western slopes of the Cascade Range, and the Black and Willapa Hills receives the full force of winter storms.Virtually every fall and winter(October through March),strong winds and heavy precipitation occur throughout the basin. Storms are frequent and may continue for several days. Successive secondary weather fronts with variable rainfall,wind, and temperatures may move onshore at daily intervals or less. 37 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Precipitation in the basin is affected by distance from the Pacific Ocean, elevation, and seasonal conditions. Generally, the southern slopes of the Olympic Range and the more easterly, higher slopes along the Cascade Range receive the greatest precipitation.The Black Hills in the northeast portion of the basin and Willapa Hills between the coast and the Centralia-Chehalis area often receive moderate to heavy rainfall during the movement of oceanic storms through the basin. The greatest amount of rainfall occurs between the months of October and March.The abundance of rainfall during this period is due to the frequent storm systems that pass over Western Washington. In Centralia and Chehalis, monthly rainfall totals for this period typically range between five and eight inches. For the rest of the year, average monthly rainfall totals range only between 0.8 and two inches. In Centralia, annual precipitation averages 41 inches,with a record low of 28 inches and a record high of 60 inches. In the Willapa Hills, the average rainfall is 120 inches per year (WA Ecology, 2017). Heavy rainfall is often carried into the region in an atmospheric river. An atmospheric river is a band of moisture in the sky that resembles a river, bringing heavy rain or snowfall that can last for days. Over the past 40 years, atmospheric rivers have caused more than 80 percent of flood damage along the west coast(NASA, 2021).The 2007 flood was caused by an atmospheric river, which brought 12 to 26 inches over a four-day period (WA Ecology, 2016). Snowfall in the region is not heavy, but potential does exist for extremely large amounts on occasion. The average annual snowfall is approximately nine inches, with recorded extreme annual maximums at 45 inches. Most of the snowfall occurs in the month of January,with the monthly average at about 4.5 inches. Snowfall occurs occasionally at Chehalis and Centralia, but warm temperatures typically limit any snow accumulation over prolonged periods. The weather station at Centralia has recorded temperature extremes of 105 to-16 degrees.The mean monthly temperature is 52 degrees with the monthly means of January and July being 39 and 65 degrees, respectively. Winds in the region rarely exceed 30 mph; winds of this speed usually only occur during the fall and winter months in conjunction with rainstorms and/or thunderstorms that pass through the vicinity. Approximately 10 percent of the winds between the months of November and February have speeds between 15 and 30 mph, compared with approximately two percent of the winds for the other months. The rest of the wind speeds typically range between zero and 15 mph, about 90 percent of the time. Wind speeds have been measured in excess of 70 mph during the winter months.The majority of the highest wind speeds measured have originated from the south and southwest directions (City of Centralia, 2008). 3.2.4 Fish and Wildlife Fish The upper Chehalis River provides habitats supporting Chinook and Coho(silver)salmon, steelhead, lamprey, and sea run cutthroat trout. In addition, native cutthroat and rainbow trout reside in the Upper Chehalis River.The Skookumchuck hatchery releases Coho salmon fingerlings supplied by in the upper Chehalis River.The mainstem of the Chehalis River from the Skookumchuck River to the Newaukum River provides water for migration of fall and spring Chinook, Coho, and chum. Limited rearing and 38 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T spawning are expected to occur in this reach.This may be attributed to high water temperatures during the summer months and urban and agriculture non-point pollution reducing river oxygen levels.The entire mainstem of the Chehalis River and 31 linear miles of tributaries are utilized by salmon. The Skookumchuck and Newaukum Rivers, primary tributaries to the Chehalis, also provide spawning and rearing waters for Coho, spring Chinook, and fall Chinook salmon. In addition, chum have been located on the North Fork of the Newaukum River. Spawning and rearing of these fish occur on the Skookumchuck River between the Skookumchuck Dam and the confluence with the Chehalis River. Above the Skookumchuck Dam, salmon use is limited due to salmon migration barriers at dam locations. All of the Skookumchuck mainstem and 41 linear miles of tributary streams are believed to currently provide salmon production. The Newaukum River watershed has four river reaches supporting vital fish habitat. All of the mainstem, 17 miles of the North Fork, and all of the South Fork are utilized for salmon production. In addition,four linear miles of the Newaukum mainstem tributaries, 41 linear miles of the north fork tributaries, and 17 miles of the south fork tributaries are used for salmon production.These streams furnish cold water temperatures and deep pools suited for maturation of adult spring Chinook. Chinook spawning within the north fork of the Newaukum River is generally restricted to the lower 10 miles because of stream diversions.The south fork of the Newaukum River below Kearney Creek generally provides the best rearing habitats for juvenile Coho and spring Chinook within the Newaukum River watershed (Lewis County, 2008). Wildlife Lewis County encompasses many different ecosystems, from evergreen coniferous forest to lowland marshes.The variety of habitats available in the County has made it ideal for numerous types of wildlife. The riparian corridors adjacent to the rivers in Lewis County are especially important to birds and small mammals because riparian areas tend to have highly diverse vegetation as well as protected access to water; many species of wildlife are dependent upon them. Passerine and water birds rely on the riparian corridors for food and nest sites. Of the 53 bird species commonly found in Lewis County, 42 (or 79 percent) are dependent upon the riparian and wetland habitats typically associated with river systems. There are four primary categories of wildlife within the Chehalis River watershed: big game, upland wildlife,furbearers, and waterfowl. Lists of birds and mammals in Lewis County are in Tables 8-8 and 8- 9, respectively. Upland wildlife account for the greatest number of species in the basin.The upper Chehalis River, above the confluence with the Newaukum River, provides habitat for big game(black tailed deer, black bear, and elk),game birds (pheasant, grouse, and pigeons), and fur-bearers (beavers, minks, muskrats, and river otters). Seasonal flooded areas along the upper Chehalis River and its tributaries create habitats for various waterfowl.The upper Chehalis River is within the Pacific Flyway for migratory birds.The Chehalis River segment above Grand Mound also supports a diversity of wildlife. Forested areas support cover for big game species such as deer, bear, and elk as well as many upland bird species. Fur-bearing animals and waterfowl found in the upper Chehalis River are also found upstream of Grand Mound. The Newaukum River basin also provides habitats for diverse wildlife. Big game includes black tailed deer, black bears, and cougar. Upland species of native blue and ruffed grouse, ring necked pheasant, mountain quail, cottontail rabbit, mourning dove,and band tailed pigeon are found in the agricultural or forested areas. Furbearers consist of beaver, muskrat, mink, raccoon,weasel, river otter, skunk, red fox, coyote, and possum. Waterfowl include mallard, pintail,wood duck, coot, Canada goose, and blue 39 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T heron. In addition,ground squirrels,forest rodents, and amphibians and reptiles are found to reside in the Newaukum River basin. Protected species of songbirds, birds of prey, and Northern spotted owl also inhabit the Chehalis River basin. Bald eagles and ospreys use all the major rivers in Lewis County, especially in the winter months. Both bald eagles and ospreys are dependent upon the riparian and shoreline habitats associated with the rivers in Lewis County for food and nest sites (Lewis County, 2008). 3.3 Development Features 3.3.1 Land Use Lewis County lies in southwestern Washington with a total landmass of 2,452 square-miles, and measures about 90 miles (east to west) by 25 miles(north to south). Incorporated and unincorporated urban growth areas are designated and zoned for urban levels of development. Incorporated cities plan for and designate land uses within their corporate boundaries consistent with adopted comprehensive plans and development regulations. Unincorporated UGAs, areas adjacent to incorporated cities, were designated consistent with the GMA and are intended for urban development. UGAs represent about 0.7 percent of the County. Such areas are expected to develop at higher intensities and eventually be annexed into the cities and zoned for residential, commercial, and industrial uses. For a full discussion of land use within incorporated cities, refer to each city's comprehensive plan. Unincorporated Lewis County land use is regulated consistent with historic and traditional land use patterns and at intensities consistent with rural levels of public services. For example, approximately three-quarters of the 2,452 square-miles of Lewis County is devoted to long-term natural resource use— timber, agriculture, or mineral. Less than one-quarter of the land is designated for rural, non-resource uses, including rural residential, commercial, and industrial uses. Under current zoning, unincorporated areas of Lewis County are classified into the following land use categories: 1. Resource Lands a. Forest Resource Land—commercial forestry activities b. Agricultural Resource Land—commercial farming activities c. Mineral Resource Land—commercial mineral extraction 2. Rural Zones a. Rural Development Districts—rural uses, including residential, limited commercial b. Small Towns—high intensity rural settlements c. Crossroad Commercial—high intensity commercial activities d. Freeway Commercial—rural interchange activities e. Rural Residential Centers—high density residential subdivisions f. Rural Area Industrial—high intensity industrial activities g. Tourist Service Areas—public recreational areas 40 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T h. Airport Obstruction Zone 3. Urban Zones a. Urban Growth Areas b. Master Planned Resorts Open space land is designated in the County Comprehensive Plan and includes parks, wilderness areas, resource lands, and corridors.The open space designation overlays other zoning and makes up about 75 percent of the County. Open space corridors follow stream and river valleys and are comprised of steep slopes, agricultural resource land, and flood hazard areas. Unlike park and recreation areas, open space lands may be either public or private ownership and are often not available to public access. Privately owned lands in flood hazard areas (over 40,000 acres)and lands currently managed by Tacoma City Light under conservation easements (over 15,000 acres) are part of this latter category. For a more complete discussion of existing and future land uses within the Chehalis River Basin, refer to the following: • Lewis County Comprehensive Plan • City of Centralia Comprehensive Plan • City of Chehalis Comprehensive Plan • City of Napavine Comprehensive Plan • Town of Pe Ell Comprehensive Plan • Growth Management Act, Chapter 36.70A RCW • Shoreline Inventory and Characterization Report 3.3.2 Critical Facilities and Infrastructure Critical facilities and infrastructure are those that are essential to the health and welfare of the population.These become especially important after a hazard event. Critical facilities typically include police and fire stations, schools, and emergency operations centers. Critical infrastructure can include the roads and bridges that provide ingress and egress and allow emergency vehicles access to those in need, and the utilities that provide water, electricity, and communication services to the community. Also included are facilities that hold or carry significant amounts of hazardous materials with a potential to impact public health and welfare in a hazard event.Through a facilitated process,the Stakeholder Committee established a definition of critical facilities for this Comprehensive Flood Hazard Management Plan that includes but is not limited to the following: A critical facility is any property that, if flooded,would result in severe consequences to public health and safety. Facilities and infrastructure that are critical to public health and safety and that are especially important following flood events include, but are not limited to: • Structures or facilities that produce, use, or store highly volatile,flammable,explosive,toxic, or water-reactive materials; • Hospitals, nursing homes, and dedicated care centers that contain occupants who may not be sufficiently mobile to avoid death or injury during a flood; • Law enforcement and detention facilities,fire stations,government facilities,vehicle and equipment storage and maintenance facilities, and emergency operations centers that are needed for flood response activities before, during and after a flood; 41 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T • Educational facilities, including K-12 and community colleges; major road and rail systems including bridges and airports; and • Public and private utility facilities that are vital to maintaining or restoring normal services to flooded areas before, during, and after a flood. An inventory of facilities that meet this definition was created and input to the computer model used to assess risk for this Flood Plan (FEMA's Hazus model).The Flood Plan used an inventory of critical facilities and infrastructure maintained by Lewis County GIS. Not all critical facilities within the Chehalis River basin are reflected in this data. Figure 3-2 shows the location of critical facilities in the planning area and Figure 3-3 shows the location of critical infrastructure. Due to the sensitivity of this information, a detailed list of facilities is not provided.The list is on file with Lewis County.Table 3-1 and Table 3-2 provide summaries of the general types of critical facilities and infrastructure in the planning area. All critical facilities and infrastructure were analyzed to help identify the flood risk and mitigation actions. Chapter 7 assesses facilities that are exposed and vulnerable to the flood hazard. Table 3-1.Critical Facilities within the Chehalis River Basin. Police Schools and Hazardous Other City and Fire Medical Educational Materials Essential Stations Care Facilities Facilities Dams Facilities Total Unincorporated 23 6 9 5 37 3 83 Chehalis 3 10 8 2 0 13 36 Centralia 2 16 9 0 0 6 33 Napavine 1 0 3 0 0 2 6 Pe Ell 1 2 1 0 0 2 6 Table 3-2. Critical Infrastructure within the Chehalis River Basin. Ci Transportation Communications Air ports Potable Water Wastewater Systems Facilities p Facilities Facilities Total Unincorporated 9 30 7 5 2 53 Chehalis 2 5 1 4 1 13 Centralia 1 2 0 3 0 6 Napavine 0 0 0 2 0 2 Pe Ell 0 0 0 0 1 1 42 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE ET Figure 3-1. Map of Critical Facilities and Infrastructure. / -../j , '-‘=„..r..tirs3v 5 Skookttmcltuck River (y •• /1'n", . Centralia �P' ♦♦ .,.,� > `,G t •4A• i.• - Chehalis Aofi ., r ._�,y • lfr Chehalis River ,.,,,� �l. r�r A /,,Pd- .t , O�. I ( *. - . 'A NI Newaukum.River ,.. �... ,t,!'.✓, �� vr;�. Napavine ♦„ :� 1 ' ..- rr Pe El ; South Fork i t . tiA Chehalis River-_,---- oat ► y , +"'�i/"" ? PERTEET '' arcs'. • '14°4, . _! y :�- �:; Winlock Legend ,:'' r�4. 1 + / Q Upper Chehalis Watershed y _+ ,, Lewis County Boundary 46. ' _..as y /� NE 100-yr Effective Floodplain(FEMA) l J *"�'@1 w -. Planning Area Watercourses ,�':� 1 i 3"'?+��i ~y - atr. A Critical Facilities&Infrastructure within County *- t Vader Critical Facilities BE.Infrastructure within Cities itt Nq, `Planning Area v s' i �0 2 4 i"�` w.. 1a - Dad 8 212021 fit t I i " Source:Offce of the Chehalis Boon.FEMA.Lewis County;ESRI F Miles *.' d" , - Road Transportation The road system in Lewis County is made up of local public and private roads, interstate, US highways, and state routes.There are over 1,888 miles of public and private roads within the County.The County maintains 1,065 miles of roadways, 196 bridges, and 5,110 culverts.The nine cities(Centralia, Chehalis, Morton, Mossyrock, Napavine, Pe Ell,Toledo,Vader, and Winlock) are responsible for their own roadways within their city limits. Unless there is an agreement between the County and the cities,the County currently maintains the roadways in the unincorporated UGAs. The Chehalis-Centralia area lays 85 miles midway between the metropolitan areas of Seattle, Washington, and Portland, Oregon. The primary north-south transportation corridor passing through Lewis County and the Cities of Centralia and Chehalis is Interstate 5. Interstate 5 passes through the Chehalis River floodplain and is affected by flooding.The roadway was closed for four days in 1996 and 2007, and two days in 2009, causing millions of dollars of freight delays(WA Ecology, 2020). 43 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T US Highway 12 traverses Lewis County from east to west and crosses the Cascade Mountains at White Pass. White Pass is the only major all-season route south of Seattle and north of the Columbia River allowing access to eastern Washington. Railroad Transportation Several rail lines are located within the Chehalis River Basin.The mainline BNSF Railway Company railroad crosses through Lewis County and the Chehalis River floodplain. Amtrak provides passenger railway service to Centralia along the BNSF rail line.There are also rail lines operated by the Puget Sound and Pacific Railroad,the Union Pacific Railroad, and Tacoma Rail. Air Transportation The Chehalis-Centralia airport is located within Chehalis city limits and provides regional services.The airport is owned by the City of Chehalis. 3.4 Demographics Some populations are at greater risk from hazard events such as floods because of decreased resources or physical abilities. Elderly people,for example, may be more likely to require additional assistance. Research has shown that people living near or below the poverty line,the elderly(especially older single men),the disabled, women, children, ethnic minorities, and renters all experience, to some degree, more severe effects from disasters than the general population (Rufat et al., 2015).These vulnerable populations may vary from the general population in risk perception, living conditions, access to information before, during and after a hazard event, capabilities during an event, and access to resources for post-disaster recovery. Indicators of vulnerability—such as disability, age, poverty, and minority race and ethnicity—often overlap spatially and often in the geographically most vulnerable locations. Detailed spatial analysis to locate areas where there are higher concentrations of vulnerable community members would help to extend focused public outreach and education to these most vulnerable citizens. This section includes demographic data for the entire Lewis County, including areas outside of the Chehalis River Basin. 3.4.1 Population Characteristics Knowledge of the composition of the population and how it has changed in the past and how it may change in the future is needed for making informed decisions about the future. Information about population is a critical part of planning because it directly relates to land needs such as housing, industry,stores, public facilities and services, and transportation.The Washington State Office of Financial Management estimated Lewis County's population at 79,480 as of April 2019, making it the 16th largest county by population in the state (OFM, 2019). Population changes are useful socio-economic indicators.A growing population generally indicates a growing economy, while a decreasing population signifies economic decline. Figure 3-2 shows the Lewis County population change from 1990 to 2019 compared to that of the State of Washington (Washington OFM, 2021).The County grew faster than the statewide average through the early-to-mid 1990s but has since had a growth rate somewhat below, and mirroring,that of the state. Table 3-3 shows the county population from 2005 to 2019. 44 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T The Washington Office of Financial Management has developed forecasts of future population as shown in Table 3-4.The projections for medium-growth expectations for Lewis County estimate a population of 89,178 in Lewis County by 2040; a 12-percent increase from 2019. Figure 3-2.Washington and Lewis County Population Change. Washington and Lewis County Population Change 3% 2.5% w 2% L1.5% ‘ \ 1% 0.5% 0% -0.5% 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 YEAR Washington Lewis County Source:OFM,2020 Table 3-3. Recent Lewis County Population Growth. Lewis County Lewis County Lewis County Year Population Year Population Year Population 2005 71,600 2010 75,455 2015 76,660 2006 72,900 2011 76,000 2016 76,890 2007 74,100 2012 76,300 2017 77,440 2008 74,700 2013 76,200 2018 78,380 2009 75,200 2014 76,300 2019 79,480 Source:OFM,2019 45 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Table 3-4. Projected Future Lewis County Population. Year Lewis County Population 2020 80,220 2025 83,425 2030 85,438 2035 87,449 2040 89,178 Source:OFM,2017 3.4.2 Age Distribution As a group,the elderly are more apt to lack the physical and economic resources necessary for response to hazard events and are more likely to suffer health-related consequences making recovery slower. They are more likely to be vision, hearing, and/or mobility impaired, and more likely to experience mental impairment or dementia. Additionally,the elderly are more likely to live in assisted-living facilities where emergency preparedness occurs at the discretion of facility operators.These facilities are typically identified as "critical facilities" by emergency managers because they require extra notice to implement evacuation. Elderly residents living in their own homes may have more difficulty evacuating their homes and could be stranded in dangerous situations.This population group is more likely to need special medical attention, which may not be readily available during natural disasters due to isolation caused by the event. Specific planning attention for the elderly is an important consideration given the current aging of the American population. Children under 14 are particularly vulnerable to disaster events because of their young age and dependence on others for basic necessities. Very young children may additionally be vulnerable to injury or sickness;this vulnerability can be worsened during a natural disaster because they may not understand the measures that need to be taken to protect themselves from the flood hazard. The overall age distribution for Lewis County is illustrated in Figure 3-3. Based on the most recent five- year estimates(2015-2019)from the US Census Bureau's American Community Survey, 20.7 percent of the planning area's population is 65 or older, compared to the state average of 15.1 percent. According to US Census data, 44.2 percent of the over-65 population has a disability of some kind and 6.7 percent have incomes below the poverty level. The Census estimates that 15.3 percent of children under 18 in Lewis County live below the poverty line (US Census, 2019). 46 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 3-3. Lewis County Age Distribution. Lewis County Age Distribution 85 years and over 80 to 84 years 75 to 79 years 70 to 74 years 65 to 69 years 60 to 64 years 55 to 59 years 50 to 54 years w 45 to 49 years L7 < 40to44years 35 to 39 years 30 to 34 years 25 to 29 years 20 to 24 years 15 to 19 years 10 to 14 years 5 to 9 years Under 5 years 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 Number of People Source:US Census,2019 3.4.3 Race, Ethnicity, and Language Research shows that minority groups are less likely to be involved in pre-disaster planning and experience higher mortality rates during a disaster event(Gibbs and Montagnino, 2006). Post-disaster recovery can be ineffective and is often characterized by cultural insensitivity. Since higher proportions of ethnic minorities live below the poverty line than the majority white population, poverty can compound vulnerability. According to the most recent five-year estimates(2015-2019)from the US Census Bureau's American Community Survey,the racial composition of the planning area is predominantly white, at 95.0 percent. The largest non-white populations are those identifying as American Indian and Alaska Native at 3.4 percent and those identifying as"some other race" at 3.0 percent. Figure 3-4 shows the racial distribution in Lewis County(US Census, 2019).Those identifying as Hispanic or Latino, of any race, make up 10.2 percent of the population. Lewis County has a 5.2 percent foreign-born population. Of the foreign-born residents, 63.9 percent were born in Latin America. Other than English,the most commonly spoken language in the planning area is Spanish,with 7.0 percent of the population speaking Spanish at home.The Census estimates that 3.6 percent of the residents speak English "less than very well" (US Census, 2019). 47 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 3-4. Lewis County Race Distribution. White, 89.9% Some Other Race 2.8% Native Hawaiian or Asian, Black or African Other Pacific 1'8�° American Indian American, Islander, and Alaskan Native, 3.2% Source:US Census,2019 3.4.4 Disabled Populations The 2010 US Census estimates that 54 million non-institutionalized Americans with disabilities live in the US.This equates to about one-in-five persons. People with disabilities are more likely to have difficulty responding to a hazard event than the general population. Local government is the first level of response to assist these individuals, and coordination of efforts to meet their access and functional needs is paramount to life safety efforts. It is important for emergency managers to distinguish between functional and medical needs in order to plan for incidents that require evacuation and sheltering. Knowing the percentage of population with a disability will allow emergency management personnel and first responders to have personnel available who can provide services needed by those with access and functional needs. According to the 2015-2019 five-year Census estimates,there are nearly 15,000 individuals with some form of disability in Lewis County, representing 19.4 percent of the total population. Of those,47 percent are ages 65 and older, and 1.1 percent are under five-years old. Over 10 percent (10.7%) of the disabled population in Lewis County are living with an ambulatory difficulty that may increase the difficulty of emergency evacuations or response (US Census, 2019). 48 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 3.5 Economy This section includes economic data for the entire Lewis County, including areas outside of the Chehalis River Basin. 3.5.1 Income In the United States, individual households are expected to use private resources to prepare for, respond to, and recover from disasters to some extent.This means that households living in poverty are disadvantaged when confronting hazards such as flooding. Additionally,the poor typically occupy more poorly built and inadequately maintained housing located in high-hazard risk areas such as floodplains and floodways. Mobile or modular homes,for example, are more susceptible to damage in floods than other types of housing. Furthermore, residents below the poverty level are less likely to have insurance to compensate for losses incurred from natural disasters.This means that residents below the poverty level have a great deal to lose during an event and are the least prepared to deal with potential losses. The events following Hurricane Katrina in 2005 illustrated that personal household economics significantly impact people's decisions on evacuation. Individuals who cannot afford gas for their cars will likely decide not to evacuate. Based on the most recent five-year estimates (2015-2019)from the US Census Bureau's American Community Survey, per capita income in Lewis County was$27,127 and the median household income was $53,484. It is estimated that about 11.8 percent of workers over the age of 16 receive an income of $75,000 to$99,999 per year and 7.5 percent of workers' incomes are above$100,000 annually.The Census Bureau estimates that 13.1 percent of the population in Lewis County lives below the poverty level (US Census, 2019). 3.5.2 Industry, Businesses, and Institutions The planning area's economy is strongly based in the education/health care/social service industry(20.8 percent of employment),followed by retail trade (13.3 percent), and manufacturing(9.8 percent). Information (1.2 percent), wholesale trade (2.5 percent), and finance and insurance, including real estate (3.5 percent) make up the smallest source of the local economy. Figure 3-5 shows the breakdown of industry types in Lewis County. (US Census, 2019) 49 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 3-5. Industry in Lewis County. Arts,entertainment, and recreation,and Manufacturing: accommodation and / 9.8% Constructiorf'� food services:9.1% 7.8% \\\ Public administration 7.3% Retail trade: 13.3% Professional, scientific,and management,and administrative and waste management services:7.3% Transportation and warehousing,and utilities:7.1% Educational services, and health care and Agriculture, social assistance:20.9% forestry,fishing and hunting,and mining: Information: 5.6% Other services, 1.2/e Finance and insurance, except public Wholesale trade: and real estate and rental administration:4.7% 2.5% and leasing:3.5% Source:US Census,2019 The Centralia-Chehalis Chamber of Commerce presented the Lewis County Economic Profile in partnership with Western Washington University in 2019, which provided a basic overview of the local economy including factors that impact it such as major employers and tourism.The Port of Chehalis and businesses located within support approximately 1,500 jobs, while over 2,100 jobs are supported by the 30 businesses within the Port of Centralia.Tourists spend approximately$35,784,000 on recreation in Lewis County annually(WWU, 2019). 3.5.3 Employment Trends and Occupations According to the 2015-2019 five-year American Community Survey, 53.4 percent of Lewis County's population 16-years old or older is in the labor force, including 64.6 percent of women in that age range and 76.1 percent of men (US Census, 2019). Figure 3-6 compares unemployment trends from 1990 through 2014 for the United States,Washington, and Lewis County, based on data from the state Employment Security Department(Washington ESD, 2021). Lewis County's unemployment rate was lowest in 2019 at 6.1 percent.The rate peaked at 13.3 percent in 2009 and has experienced a sharp decline since then. However, due to the onset of the COVID-19 Pandemic in the United States in March 2020,the unemployment rate for Lewis County,the State of Washington, and the United States as a whole, increased sharply. 50 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 3-6. US,Washington,and Lewis County Unemployment Rate. US, Washington, and Lewis County Unemployment Rate 14% 12% 10% 8% 6% 4% 2% 0% 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 Lewis County -Washington US Source:ESD,2021 Figure 3-9 shows US Census estimates of employment distribution by occupation category(US Census, 2013). Management, business, science, and arts occupations make up 27.8 percent of the jobs in Lewis County.Sales and office occupations make up 21 percent. The US Census estimates that 79.5 percent of workers in the County commute alone (by car,truck, or van)to work(US Census, 2019). 51 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 3-9.Occupations in Lewis County. Production, transportation,and Management, material moving business,science,and occupations: 17.3% arts occupations: 27.8% Natural resources, construction,and maintenance occupations: 13.9% Service occupations: 20.0% Sales and office occupations: 21.0% Source:2019 US Census 52 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 4.0 REGIONAL CONSISTENCY 4.1 Regional Plan Coordination The Chehalis River Basin has a long history of flooding.After the devastating flooding in 2007, communities within the watershed organized together to form the Chehalis River Basin Flood Authority (Flood Authority) in 2008. Founding documents were signed by Lewis County, Grays Harbor County, Thurston County,the Chehalis Tribe, and cities of Centralia, Chehalis, Aberdeen, Montesano, and Towns of Pe Ell and Bucoda. Over time,the Cities of Oakville, Cosmopolis, Napavine, and Hoquiam also joined as members. The purpose of the Flood Authority is to work with project sponsors to identify and fund mitigation projects that address flooding problems throughout the basin using a coordinated approach.The goal is to reduce flood damage while improving floodplain functions. Since 2008,the Flood Authority has sponsored local level projects, such as retrofit programs for private property, regulatory projects such as reviews and analysis of local regulations, and regional projects such as developing and managing a flood warning system for the entire watershed and planning for a flood retention facility at the headwaters of the river. At the same time,the Chehalis Basin Strategy was created to reduce flooding damage and improve fish and wildlife habitat. In 2016,the Office of the Chehalis Basin was formed within the Department of Ecology to manage the Chehalis Basin Strategy. Since its creation,the Chehalis Basin Strategy has conducted and/or reviewed almost 1,000 studies across the basin,gathered input and ideas from the public, identified options for both large-scale and community-scale flood damage reduction projects, and developed a draft Aquatic Species Restoration Plan. In 2017,the Department of Ecology released the Final Programmatic Environmental Impact Statement to evaluate the overall strategy to reduce flooding in the basin. In 2020,the Department of Ecology released a draft SEPA Environmental Impact Statement and the Army Corps of Engineers released a draft NEPA Environmental Impact Statement to evaluate specific actions within the Strategy: the proposed flood retention facility at the headwaters of the Chehalis River in Lewis County and a levee at the Chehalis-Centralia Airport Currently,the Flood Authority and the Office of the Chehalis Basin are separate entities managed by separate boards, but with the same goal of implementing the Strategy. The Flood Authority generally focuses on local level projects, and the Office of the Chehalis Basin is focused on large scale regional projects, individual landowner projects, and community-scale projects. In 2011,the Chehalis Basin Flood Control Zone District was formed within Lewis County to manage local flooding issues.This Flood Plan will establish a true coordinated plan in support of all flood risk reduction within Lewis County's Chehalis River Basin and will be maintained and implemented by the Chehalis River Basin Flood Control Zone District.The Chehalis River Basin Flood Control Zone District is the project sponsor and applicant for the flood retention facility and airport levee. For more information on the proposed Chehalis Basin Strategy actions proposed within Lewis County, see Section 12.6. 53 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 4.2 Regional Plan Consistency Review This plan was developed to meet the needs specific to Lewis County and the Flood Control Zone District but remain consistent with the overall goals of the watershed. Several agencies or organizations have plans that encompass or include this Flood Plan's study area.The project team reviewed the following plans to ensure consistency in regional planning efforts: • 2010 Chehalis River Basin Comprehensive Flood Hazard Management Plan. Chehalis River Basin Flood Authority. • Chehalis Basin Strategy: Reducing Flood Damage and Enhancing Aquatic Species. September 16, 2014. • Chehalis River Basin Floodplain Management Assessment Master Report.April 2015. • Comprehensive Flood Hazard Management Plan for Confederated Tribes of the Chehalis Reservation. March 17, 2009. • City of Centralia Comprehensive Flood Management and Natural Hazards Mitigation Plan. December 9, 2008. • Hazard Identification and Vulnerability Analysis. August 31, 2018. • Lewis County Multi-jurisdictional Hazard Mitigation Plan.January 25, 2016. • Lewis County Comprehensive Flood Hazard Management Plan. May 2004. • Lewis County Comprehensive Flood Hazard Management Plan. September 2008. • Lewis County Comprehensive Plan. 2020. • City of Centralia Comprehensive Plan. 2018. • City of Chehalis Comprehensive Plan. 2017. • Lewis County Shoreline Management Program. 2017. • Shoreline Inventory and Characterization Report for Lewis County. October 17, 2013. In addition to the plans listed above,the planning team reviewed several documents, reports, and studies prepared over the past years to inform the Chehalis Basin Strategy. Many of these documents were used in the preparation of this plan to inform the risk assessment, describe the hazard, and identify actions.All documents used in the preparation of this report are listed within the references in Section 15 and are cited in the text throughout the document. Some of these documents include: • Chehalis Basin Strategy Final Programmatic Environmental Impact Statement. June 2017. (WA Ecology, 2017) • State Environmental Policy Act Draft Environmental Impact Statement for the Proposed Chehalis River Basin Flood Damage Reduction Project. February 27, 2020. (WA Ecology, 2020) • NEPA Draft Environmental Impact Statement Chehalis River Basin Flood Damage Reduction Project. September 18, 2020. • Lewis County Recovery Strategy. April 2009. (Lewis County, 2009b) • FEMA NFIP Policy and Claims Information. May 2021. (FEMA, 2021c) • FEMA Flood Insurance Study for Lewis County. July 17, 2006. (FEMA, 2006) • USGS Stream Gage Data. May 2021. (NWS, 2021) 54 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T PART 2 — RISK ASSESSMENT 5.0 RISK ASSESSMENT METHODOLOGY 5.1 Purpose of Risk Assessment This part of the Flood Plan evaluates the risk of the flood hazard in the planning area (CRS Step 5). Risk assessment is the process of measuring the potential loss of life, personal injury, economic injury, and property damage resulting from natural hazards such as flooding. It allows emergency management personnel to establish early response priorities by identifying potential hazards and vulnerable assets. The process focuses on the following elements: • Exposure identification—Determine the extent of people, property, environment, and economy exposed to the effects of the natural hazard. • Vulnerability evaluation—Estimate potential damage from the natural hazard and associated costs. The risk assessment describes the flooding hazard,the planning area's vulnerabilities, and probable event scenarios.The following steps were used to define the risk: • Identify and profile the flooding hazard (CRS Step 4); o Principal sources of flooding in the planning area o Major past flood events o Geographic areas most affected by floods o Estimated flood event frequency o Estimates of flood severity o Warning time likely to be available for response o Existing flood protection programs and projects o Secondary hazards associated with the flood hazard o Potential impacts of climate change on flooding o Expected future trends that could affect the flood hazard o Scenario of potential worst-case flood event o Key issues related to flood hazard management in the planning area. • Determine exposure to the flood hazard—Exposure was determined by overlaying flood maps with an inventory of structures,facilities, and systems to determine which of them would be exposed to flood events. • Assess the vulnerability of exposed facilities—Vulnerability of exposed structures and infrastructure was determined by interpreting the probability of occurrence of each flood event and assessing structures, facilities, and systems that are exposed. In addition,the repetitive loss areas in the County were reviewed, mapped, and evaluated. 55 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 5.2 Risk Assessment Approach 5.2.1 FEMA's Hazus Software In 1997, FEMA developed the standardized Hazards US (Hazus) model to estimate losses caused by earthquakes and identify areas that face the highest risk and potential for loss. Hazus was later expanded into a multi-hazard methodology, Hazus-MH, with new models for estimating potential losses from hurricanes and floods.The use of Hazus for hazard mitigation planning offers numerous advantages: • Provides a consistent methodology for assessing risk across geographic and political entities. • Provides a way to save data so that it can readily be updated as population, inventory,and other factors change and as mitigation planning efforts evolve. • Facilitates FEMA review of mitigation plans because it helps to ensure that FEMA methodologies are incorporated. • Supports grant applications by calculating benefits using FEMA definitions and terminology. • Produces hazard data and loss estimates that can be used in communication with local stakeholders. • Is administered by the local government and can be used to manage and update a flood hazard management plan throughout its implementation. Hazus is a GIS-based software program that includes extensive inventory data, such as demographics, building stock, critical facilities,transportation facilities and utilities. It uses multiple models to estimate potential losses from natural disasters.The program maps hazard areas and estimates damage and economic losses for buildings and infrastructure. To estimate damage that would result from a flood, Hazus uses pre-defined relationships between flood depth at a structure and resulting damage, with damage given as a percent of total replacement cost. These are referred to as depth-damage curves and are based on data from the Federal Insurance Administration and the Corps of Engineers. Curves defining these relationships have been developed for damage to structures and for damage to typical contents for a variety of residential, commercial, and public structures. By inputting flood depth data and known property replacement cost values, users can generate dollar-value estimates of damage that will result from any given flood event. Hazus provides default data for inventory,vulnerability, and hazards;this default data can be supplemented with local data to provide a more refined analysis.The model can carry out three levels of analysis, depending on the format and level of detail of information: • Level 1—All of the information needed to produce an estimate of losses is included in the software's default data.This data is derived from national databases and describes in general terms the characteristic parameters of the modeled area. • Level 2—More accurate estimates of losses require more detailed information about the modeled area.To produce Level 2 estimates of losses, detailed information is required about local geology, hydrology, hydraulics and building inventory, as well as data about utilities and critical facilities.This information is needed in a GIS format. • Level 3—This level of analysis generates the most accurate estimate of losses. It requires detailed engineering and geotechnical information to customize it for the modeled area. Level 3 56 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T involves establishing new damage curves,which is not necessary for flood hazard analyses, because those damage functions are well established. To assess the flood hazard for this Flood Plan, a Level 2, user-defined analysis was performed for both general building stock and critical facilities. Findings from this analysis are covered in Chapter 7. 5.2.2 Sources of Data Used in Hazus Modeling Data loaded into Hazus included property replacement cost values and detailed structure information derived from address, parcel, and tax assessor data provided by Lewis County. When available, an updated inventory was used in place of the Hazus defaults for critical facilities and infrastructure. Replacement cost is the cost to replace the entire structure with one of equal quality and utility. Replacement cost is based on industry-standard cost-estimation models published in RS Means Square Foot Costs. It is calculated using the RS Means square foot cost for a structure, which is based on the Hazus occupancy class(e.g., multi-family residential, commercial retail trade), multiplied by the square footage of the structure from the tax assessor data. For single-family residential structures,the construction class and number of stories factor into determining the square foot costs. Flood hazard areas for the 100-year effective flood were delineated using new FEMA digital flood data where available (from Digital Flood Insurance Rate Maps) and older FEMA digital flood data (Q3 data) where digital mapping has not yet been developed. Lewis County supplemented the Q3 data by digitizing the floodways and base flood elevations into GIS.Table 5-1 summarizes the sources of data used in the Hazus model for this Flood Plan. 5.2.3 Flood Depth Grids An important input to Hazus for modeling flood damage is a flood depth grid, which defines the depth of floodwater at points covering the flooded area for any given flood event. For this Flood Plan, the Office of the Chehalis Basin provided depth grids to the Planning Team that were imported directly into Hazus. The following depth grids were provided: • 100-year modeled floodplain • 100-year modeled floodplain with flood reduction projects • 10-year modeled floodplain • 10-year modeled floodplain with flood reduction projects • Climate change modeled floodplain (mid-range) • Climate change modeled floodplain with flood reduction projects (mid-range) The depth grids do not include all tributaries into the Chehalis River that have FEMA identified 100-year floodplains; therefore,the results cannot be directly compared to the effective 100-year floodplain Hazus results within the unincorporated county. See Section 7.1 for more information on the differences between the floodplain boundaries. The climate change model is based on the "mid-range" projections estimating a 26 percent flow increase.See Section 9.4.3 for more information on the climate change model. 57 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T The flood reduction projects are described in Section 12.1. To develop the FEMA 100-year effective Hazus model,the County provided the Planning Team used digitized effective FIRM data provided by Lewis County to generate a depth grid within Hazus. Table 5-1. Hazus Model Data Documentation. Data Source Date Format Building information for residential, commercial, Lewis County 2019 Digital (GIS)format and mobile homes (square footage, use description,year built, number of stories,garage type, construction class, building material, foundation type) Chehalis Basin Finished Floor Analysis—2017 Anchor QEA, 2017 Digital (GIS)format Update Watershed Science & Engineering (WSE) Building replacement cost RS Means 2019 Paper format Population data (2010 U.S. Census) Hazus v4.2 SP03 2010 Digital (GIS and tabular)format FEMA Effective Digital Flood Insurance Rate Map FEMA 07/2006 Digital (GIS) format data FEMA Flood Insurance Rate Maps Lewis County 1981, 1982 Digital (GIS)format Depth grids Anchor QEA 2019 Digital (GIS)format LiDAR digital elevation model, 6-foot horizontal Puget Sound LiDAR 2012 Digital (raster) resolution Consortium (PSLC) format Digital elevation model, 10-meter horizontal US Geological Unknown Digital (raster) resolution Survey format 5.2.4 Limitations Loss estimates, exposure assessments and vulnerability evaluations rely on the best available data and methodologies. However, results are subject to uncertainties associated with the following factors: • Incomplete scientific knowledge about flood hazards and their effects on the built environment. • Approximations and simplifications necessary to conduct a study. • Incomplete or outdated inventory, demographic, or economic parameter data. • The unique nature,geographic extent, and severity of the flood hazard. • Mitigation actions already employed. • The amount of advance notice residents have to prepare for a flood event. • FEMA adheres to a protocol for map revision. Understanding that flood hazard areas are dynamic and constantly changing, FEMA attempts to keep its maps current by adhering to this protocol.At any point in time a current map may not reflect current conditions. 58 NOVEMBER 2021 1 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T These factors can affect loss estimates by a factor of two or more.Therefore, potential exposure and loss estimates are approximate.The results do not predict precise results and should be used only to understand relative risk. 59 NOVEMBER 2021 l COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 6.0 LEWIS COUNTY FLOOD PROFILE 6.1 General Concepts A floodplain is the area adjacent to a flood source such as a river, creek, alluvial fan, or lake that becomes inundated during a flood. Floodplains may be broad, as when a river crosses an extensive flat landscape, or narrow, as when a river is confined in a canyon. When floodwaters recede after a flood event,they leave behind layers of rock and mud.These gradually build up to create a new floor of the floodplain. Floodplains generally contain unconsolidated sediments (accumulations of sand,gravel, loam, silt, and/or clay), often extending below the bed of the stream. These sediments provide a natural filtering system,with water percolating back into the ground and replenishing groundwater.These are often important aquifers,the water drawn from them being filtered compared to the water in the stream. Fertile,flat, reclaimed floodplain lands are commonly used for agriculture, commerce, and residential development. Connections between a river and its floodplain are most apparent during and after major flood events. These areas form a complex physical and biological system that not only supports a variety of natural resources but also provides natural flood and erosion control. When a river is separated from its floodplain with levees and other flood control facilities, natural, built-in benefits can be altered or significantly reduced. 6.1.1 Measuring Floods and Floodplains The frequency and severity of flooding are measured using a DEFINITIONS discharge probability, which is the probability that a certain river discharge (flow) level will be equaled or exceeded in a Flood—The inundation of given year. Flood studies use historical records to determine normally dry land resulting from the probability of occurrence for the different discharge levels. the overland flow of water from The flood frequency equals 100 divided by the discharge any source. probability. For example,the 100-year discharge has a one- percent chance of being equaled or exceeded in any given Floodplain—The land area along year.The"annual flood" is the greatest flood event expected the sides of a body of water that to occur in a typical year.These measurements reflect becomes inundated with water statistical averages only; it is possible for two or more floods during a flood. with a 100-year or higher recurrence interval to occur in a short time period.The same flood can have different 100-Year Floodplain—The area recurrence intervals at different points on a river. flooded by a flood event that has a one-percent chance of being The extent of flooding associated with a one-percent annual equaled or exceeded each year. probability of occurrence (the base flood or 100-year flood) is This is a statistical average only; a used as the regulatory boundary by many agencies.Also 100 year flood can occur more referred to as the special flood hazard area (SFHA),this than once in a short period of boundary is a convenient tool for assessing vulnerability and time.The one percent annual risk in flood-prone communities. Many communities have chance flood is the standard used maps that show the extent and likely depth of flooding for the by most federal and state base flood. Corresponding water-surface elevations describe agencies. 60 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T the elevation of water that will result from a given discharge level, which is one of the most important factors used in estimating flood damage. 6.1.2 Floodplain Ecosystems Floodplains can support ecosystems that are rich in plant and animal species.A floodplain can contain 100 or even 1,000 times as many species as a river. Wetting of the floodplain soil releases an immediate surge of nutrients: those left over from the last flood, and those that result from the rapid decomposition of organic matter that has accumulated since then. Microscopic organisms thrive and larger species enter a rapid breeding cycle. Opportunistic feeders(particularly birds) move in to take advantage.The production of nutrients peaks and falls away quickly, but the surge of new growth endures for some time. Species growing in floodplains are markedly different from those that grow outside floodplains. For instance, riparian trees (trees that grow in floodplains)tend to be very tolerant of root disturbance and very quick growing compared to non-riparian trees. 6.1.3 Effects of Human Activities Because they border water bodies,floodplains have historically been popular sites to establish settlements. Human activities tend to concentrate in floodplains for several reasons:water is readily available; land is fertile and suitable for farming; transportation by water is easily accessible; and land is flatter and easier to develop. But human activity in floodplains frequently interferes with the natural function of floodplains. It can affect the distribution and timing of drainage,thereby increasing flood problems. Human development can create local flooding problems by altering or confining drainage channels.This increases flood potential in two ways: it reduces the stream's capacity to contain flows, and it increases flow rates or velocities downstream during all stages of a flood event. Human activities can interface effectively with a floodplain if steps are taken to mitigate the activities' adverse impacts on floodplain functions. 6.2 Principal Types of Flooding in the Chehalis River Basin Stage flooding is the most common types of flooding that occurs in the Chehalis River Basin. Stage flooding occurs during periods of heavy rains, and flooding can last several days after a storm. Flash flooding occurs during the summer with cloudburst-type rainstorms, in the winter with extremely heavy rainfall, or when debris dams the river and suddenly bursts. Since 1880,the Chehalis River Basin within Lewis County has experienced flooding ever 4.7 years on average (Lewis County, 2009b). 6.2.1 Stage Flooding Stage flooding is largely the result of heavy rain events due to atmospheric rivers, and to a lesser degree to rain-on-snow events. Atmospheric rivers funnel large quantities of precipitation in a short time span. (WA Ecology, 2017)The magnitude and duration of stage floods can vary significantly depending on the quantity of precipitation, where the precipitation is falling, and duration of storm events(Lewis County, 2008). Stage flooding is prevalent in the flat river valley surrounding Centralia and Chehalis, where water rises and inundates large areas of the cities and county. Areas that regularly become inundated along the mainstem Chehalis River—including backwater flooding on Coffee, China, Salzer, and Dillenbaugh Creeks—typically contain slow-moving water. Inundation by floodwaters disrupts transportation routes such as 1-5,the main north south transportation route between Seattle and Portland;forces evacuation 61 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN p E RT E E T of homes and commercial establishments; and can temporarily put sewage treatment plants out of service. A main line of the Burlington Northern Railroad also crosses the floodplain from east to west on the Chehalis River near Chehalis.The tracks are subject to damage at various locations during large floods. The Chehalis-Centralia airport is protected by a dike system, but the dikes were overtopped during the January 1990 and December 2007 flood event, closing the airport(Lewis County, 2008). Figure 6-1.The Science Behind Atmospheric Rivers. The science behind atmospheric rivers An atmospheric river(AR)is a flowing column of condensed water vapor in the atmosphere responsible for producing significant levels of rain and snow, especially in the Western United States.When ARs move inland and sweep over the mountains,the water vapor rises and cools to create heavy precipitation. Though many ARs are weak systems that simply provide beneficial rain or snow,some of the larger,more powerful ARs can create extreme rainfall and floods capable of disrupting travel,inducing mudslides and causing catastrophic damage to life and property.Visit www.research.noaa.gov to learn more. r A strong AR transports an amount of water vapor roughly t it/ � ot equivalent to 7.5-15 times the average flow of water at the mouth of the Mississippi River. ARs are a primary feature in the entire global water " n 1.16 cycle and are tied closely to both water supply and - WATER • * �i Y flood risks,particularly in the Western U.S. VAPOR ,} COOLS j On average,about 30-50%of annual ,.. • "•(r s precipitation on the West Coast occurs a r'4 1'r.. ,� 1 In just a few AR events and contributes • , w 4 } to the water supply—and a , flooding risk. y}7� ,r Y � ARs move with the weather and 9y 1• are present somewhere on c, •, y _ ' Earth at any given time. s ARs are approximately �) :. 250-375 miles wide on 1 NIA y. + + -, x '"' � a� aversg e. "\ / + + w • _ Scientists'improved understanding of ARs has come Rollo • , • - ,,a '�• fP roughly a decade of scientific studies that use observe' 'b ^,*.,. 'rm i► s+ satellites,radar and aircraft as well as the latest numerical ,4� ' models.More studies are underway,including a 2015 scientific Life. ' mission that added data from instruments aboard a NOM ship. . '` • `,fir Source:NOAA 6.2.2 Flash Flooding Flash flooding is flooding characterized by a quick rise and fall of water level from intense rainstorms or debris dams bursting. Flooding during the 2007 flood was characterized as flash flooding due to debris that clogged the river, which released as a 4-to 18-foot wall of water that"crashed through the blockages and ripped through the valley floor(Lewis County, 2009b)." 6.3 Major Flood Events Presidential disaster declarations are typically issued for hazard events that cause more damage than state and local governments can handle without assistance from the federal government, although no specific dollar loss threshold has been established for these declarations.A presidential disaster declaration puts federal recovery programs into motion to help disaster victims, businesses, and public entities. Some of the programs are matched by state programs. Lewis County has experienced 19 flood 62 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T events since 1964 for which presidential disaster declarations were issued, as summarized in Table 6-1, and many more floods that did not qualify as a presidential disaster declaration.Table 6-1 contains presidential disaster declarations for the entire county, including outside of the Chehalis River Basin. Review of these events helps identify targets for risk reduction and ways to increase a community's capability to avoid large-scale future events. Still, many flood events do not trigger federal disaster declarations, but have significant impacts on the communities impacted.These events are also important to consider in establishing recurrence intervals for flooding.The following sections provide an overview of some of the more significant floods in the County. Table 6-1. Presidential Disaster Declarations in Lewis County. DR# Declaration Title Incident Start Date Watershed 185 Heavy rains and flooding December 29, 1964 N/A 300 Heavy rains, melting snows, and flooding February 9, 1971 Chehalis 322 Severe storms and flooding February 1, 1972 Chehalis 414 Severe storms, snowmelt, and flooding January 25, 1974 N/A 492 Severe storms and flooding December 13, 1975 Cowlitz 545 Severe storms, mudslides, and flooding December 10, 1977 Cowlitz 784 Severe storms and flooding November 22, 1986 Chehalis 852 Severe storms and flooding January 6, 1990 Chehalis 883 Severe storms and flooding November 9, 1990 Chehalis 896 Severe storms and high tides December 20, 1990 Nisqually 981 Severe storms and high wind January 20, 1993 Chehalis 1079 Severe storms, high wind, and flooding November 7, 1995 Cowlitz 1100 High winds, severe storms, and flooding January 26, 1996 Chehalis, Cowlitz 1734 Severe winter storm, landslides, mudslides, and December 1, 2007 Chehalis flooding 1817 Severe winter storm, landslides, mudslides, and January 6, 2009 Chehalis flooding 4253 Severe winter storm, straight-line winds, December 1, 2015 Chehalis, flooding, landslides, mudslides, and a tornado Cowlitz 4309 Severe winter storms,flooding, landslides, January 30, 2017 Chehalis mudslides 4539 Severe storms,flooding, landslides, and January 20, 2020 Chehalis mudslides 4593 Severe winter storms, straight-line winds, December 29, 2020 Chehalis flooding, landslides, and mudslides Source:FEMA,2021a;Lewis County,2016 6.3.1 2007 Chehalis River Flood The December 2007 Chehalis River Flood is the current flood of record for Lewis County and is estimated to have a recurrence interval of 500-years in the upper watershed and 100-year in the Chehalis and 63 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Centralia area, breaking several records for peak flows. In the upper watershed near the headwaters in the Willapa Hills, stream flow was more than double their previous peak and more than 67 percent greater than the current 100-year flood estimates.The storm caused flooding records to be set at Grand Mound, Porter, Doty, and the South Fork Chehalis gaging stations. (WATERSHED, 2012) Cause An atmospheric river brought record rainfall to the Willapa Hills beginning December 1, 2007. Figure 6-2 shows a satellite photo of the storm system. By December 3, 2007, rainfall in the Willapa Hills reached 14-inches of rainfall in 24 hours, setting a record for 24-hour precipitation totals.The stream gage in Doty rose from three-feet to thirty-feet in seventeen hours.At one point, there was about 12-feet of flowing water over Interstate 5. Figure 6-2.Satellite Photo of December 2007 Storm System. ,T.- R! �9 f 6 ` _ .i • e 7. "'> i. fiF idle - y . s , a . !! a it 1111 i. .1 , i or l ,+ y.„ *T • ` .a t . j t,{3 Source:Lewis County,2009b Damages The 2007 storm caused an estimated $166 million in damages in Lewis County alone.The Lewis County 2007 Flood Recovery Strategy released in 2009 (Lewis County, 2009b)summarized the following damage or destruction: • 1,262 residential structures damaged or destroyed (779 within UGAs) • 239 commercial/industrial structures damaged or destroyed (178 within UGAs) • 10 fire district vehicles damaged or destroyed • Five fire district stations damaged or destroyed • 10,077 acres of farmland impacted 64 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • 4,776 acres of farmland debris cleanup • 227,778 linear feet of fence damaged • 1,886 acres of farmland re-seeded • 1,836 linear feet of ditch cleaned • 1,600 commercial livestock disposed (400 cattle) • 1,655 landslides mapped (actual number estimated to be 30-50 percent greater) • $1,524,960 of damages to County roads • $4,479,000 of damages to state highways within Lewis County • $47,070,000 economic impact from four-day 1-5 closure • 26-day full closure of SR 6, and 47-day partial closure with flaggers • $1,513,307 of Port of Chehalis rail line and bridge repairs • $346,164 of damages at Chehalis-Centralia Airport • 2,552 documented drums and containers recovered • 793 documented tires recovered • $14,933,782 allocated to Lewis County from FEMA • $68,321,072 allocated to Lewis County from FHWA • $40,338,076 in flood insurance claims • $23,314,900 in SBA loans approved The Lewis County December 3, 2007, Chehalis River Flooding Event Description (Lewis County, 2009a) summarized the following: • $45,000,000 in local business inventory losses, damages, clean-up costs, and lost revenue • 500 rescues were performed, using 25 boats and 7 helicopters • The Boistfort water system was out of service for over three months • 400 school children were reported to be homeless after the flood 6.3.2 Other Historical Flooding Events The following are notable flooding events in Lewis County(McDonald, 2007): • December 1887—The earliest significant flood documented in the Chehalis and Centralia area. • November 1909—A rain and windstorm caused damage to roads, railroad tracks, and mills. Floodwater may have been the highest in 25-years. • December 1915—Heavy rains cause worst storm in city's history, according to long-time residents. Flooding occurred throughout the basin. • January 1919—Newspapers declare flood to be worst in city's history. • December 1933—Torrential rainfall designated December 1933 as the wettest month in history and causes flooding that leads to severe damage or transportation infrastructure. • December 1937—Rainfall causes the severe flooding, currently designated at the 8th highest flood at the Ground Mound gaging station. • January 1972—A rainstorm caused an all-time high in Centralia, which currently ranks as the 7th highest flood at the Centralia gage station and the 9th highest flood at the Ground Mound 65 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T gaging station. News reports document 1-5 flooding, log jams, and debris flows and declared the flood to be the worst in history. • November 1986—A storm caused the 4th worst flood at the time,flooding the interstate, county roads, and schools. A wood treatment plant in Chehalis flooded, releasing 10,000 gallons of improperly stored pentachlorophenol (PCP), creosote, and other hazardous chemicals into floodwaters that inundated residential neighborhoods.The site became a superfund in 1989 and was delisted in 2020. • 1990—Six inches of rain in six days in January led to heavy flooding and all-time highs at the time on the Skookumchuck River and Chehalis River. Additional flooding occurred in February and November. • February 1996—Heavy rainfall caused wide-spread flooding throughout Washington, and at the time a record setting peaks on the Skookumchuck River and Chehalis River. Water levels exceeded the estimated 100-year flood,which led Centralia to begin requiring homes to be elevated one-foot above the 1996 flood levels.The flood currently ranks the second highest flood at the Ground Mound gaging station and remains the highest flood on the Skookumchuck River. • December 2007—The current highest flood at the Ground Mound gaging station. • January 2009—Heavy rain caused high flows throughout the Chehalis River basin.The flood was the 5th largest flood in 82 years of records at the Grand Mound gaging station, and the 7th largest in 71 years at the Doty gaging station (WATERSHED, 2012). • December 2015—Heavy rain caused flooding county-wide.Along the Cowlitz,flood was reported to be the worst since 2006 rescues and road closures due to road damage (The Chronicle, 2015). 6.4 Location Lewis County has significant floodplains county-wide.Within the Chehalis River Basin,floodplains with detailed studies are designated along the Chehalis River, South Fork Chehalis River, Elk Creek, Sand Creek, Lake Creek, Stearns Creek, Newaukum River, Berwick Creek, Dillenbaugh Creek, Coal Creek, Salzer Creek, China Creek, Skookumchuck River, Coffee Creek, and Hanaford Creek. There are several creeks with approximate floodplains, and there are other unmapped flood hazard areas throughout the County.The hazard areas range from urban settings around the cities of Centralia, Chehalis, Pe Ell, and Napavine to rural areas along the smaller tributaries. Several creeks and rivers feed into the Chehalis River within or near the cities, creating converging flooding hazards from different sub-watersheds. In Chehalis, the Newaukum River and Dillenbaugh Creek merge into the Chehalis River on the south. Dillenbaugh Creek flows through the city on the east side of 1-5, creating flood hazards on both sides of the freeway. On the north end of Chehalis, Coal Creek and Salzer Creek merge together before crossing under 1-5 and joining the Chehalis River. Centralia's flood hazards include Coal Creek at the south end, China Creek near the middle, and the Skookumchuck River and China Creek near the north. Flooding in portions of the planning area has been extensively documented by gage records, high water marks, damage surveys, and personal accounts. Several sources of flood data exist.To map the extent and location of the flood hazards for this plan based on the effective regulatory floodplain,the 2006 Flood Insurance Study(special flood hazard areas)was used.To map actual conditions with more 66 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PERTEET current data,the plan referenced depth grids generated in 2019 for the 100-year flood (similar boundaries to the 2007 flood),the 100-year climate change flood, and the 10-year flood. See Figures 6-3 to 6-7 for maps showing boundaries of the floodplains used for this analysis. These maps also include the effective 100-year floodplain to demonstrate the limitations in the ability to compare the data. While viewing these maps, it is important to understand that in several areas the boundaries of the floodplains appear similar. However,this is due to floodwaters reaching its limit. Once the limit is reached instead of spreading wider,floodwaters get deeper. Figure 6-4 identifies the area of Lewis County that has Digital Flood Insurance Rate Maps (DFIRM) as the effective map. Only the cities of Chehalis and Napavine are entirely covered by the DFIRMs. Figure 6-3. 100-Year Effective Floodplain with Floodway. r3 1 5 Slack kunichuck f e,,y �'1 River I - J - Centralia . 'fir,_ ' ,.�_ �l'` ' !4 d^ 4. 'Sr� �y',` Chehalis River Chehalis '°'r�T' rt !,, r fTIj t�rr 1i , d 1i ♦, 0� l- , „,.. ; New' au River `"-� ",�' ' \ _ - /� $ Napavineilk j :-,(!li,,,----,' , South Fork4'Pe / * ''".,_ Chehalis River f. : • _ , ,� 7 'r ,I+ =' 12 .7 PERTEET , - .. ^,;. ... Winlock 1 -. 4 de . v - 't '' 4 /,` '-- Legend f- 4 J%-• _+ s" , .....a' Q Upper Chehalis Watershed �w r.,,. A .. . caLewis County Boundary *ILdti `� 7 .ii ' NE 100-yr Effective Floodplain(FEMA) ilillM Floodway ..e'"'" ��Vader�' Planning Area Watercourses 4 ------______.__ .__—__---- ---- Planning Area N . ,' 0 2 4 ', Date:10/15/2021 ! ;�. r t s i '- 10 Source:Office of the ChehoI Basin,FEMA,Lewis County:ESRI V Miles 67 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T Figure 6-4. 100-Year Effective Floodplain (DFIRM)with Flood Zones. l �, `� # 2'' PERTEET r 1Nfr. ' ' .� Legend t fit 100-yr Effective Floodplain(FEMA) ,....,:i:iiie 4 , • Floodway i (_i PlanninCitiesg Area Watercourses Chehalis River y r >r .4. `�.�1" s / . flie, ow500-yr Effective Floodplain(DFIRM) / 'IF,: IIII.Floodway(DFIRM) Chehalis , A Zone(DFIRM) r AE Zone(DFIRM) AH Zone(DFIRM) •A. iii i Dote:I0A52021 ~ Sooree:Offee ofthe Chehalis Bosin.FEMA,Lewis Count;ESRI �I %, ) J 120 Y ft e taamilr - �� irk ' �. -� A' A `, I/ e ."a Vewaultum River ' 0 rt,, Napavine 2 4 \- I i t t I M i le s --,� 68 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 6-5. 100-Year Modeled Floodplain. ......,„_____ f--- i N c-C 5 Skookumehuck ' r... CO ,/-Ri , ver I 1 I , il ,, ' ...../.". 1 './"*.:- --4 Centralia • 1,4, , . , i..pr .".j f --":1 '' '' ' ..,• ,rr Ch I alis eh , - t t 7 -o•felr' 0,- - - ,. • , • ...-P4''' Chehalis River ,.., • i.,--,--\/ f ....k. ?AP"' \ i • 4/412/,4 d , e- -- --- - 4. 46- N ewaukum River -,.. \,.....-- 1 i %--' . - ,' 44,........,,, ,L-,, ./. .' , NapavIney.. = ..," .-, , (Pe - I If-;,..-..;-":r.':',.:1 "•-•- •• - • South Fork\ f Z) • .1 ' . st • ...';* ' r -_7);•i(•:;,?... ''--,„'''• '. ._',,.- Ch e,. ha1 lis River...0.- ' Ar: :. - -\ , 7 t )r0r, PERT' E. ETN Wi n lock Legend =I Upper Chehalis Watershed ' ! ,-......! -- , •.,., , . tr," • \ AA'.' -.- : -0# •,,, Me-t'. .40-, - C:3 Lewis County Boundary ..., _ ; , : ''—'". .:.---- p ' NM 100-Year Modeled Floodplain =100-yr Effective Floodplain(FEMA) ,..4--': ''!' (4.0.:411 ;. ' /-**-s, I" — Planning Area Watercourses Nader =Planning Area N , .... ....., , 1.../ 1_,_i__I__i_j :11ki:•, i — Source:M Offce of the Chehalis Basin,FEMA.Lewis County;ESRI ...,' . iles - 69 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 6-6. 100-Year Climate Change Floodplain. f , r :-4,, i r« .. 5 . Skookumchu��ckii ii, 1 River i ,...' t-- WIF*17 ------,,-,.„ --- -_,,,.... '1._ = .;'+r;„ - Centralia �`' - T . c'—'w1 .- i- : ,:' Chehalis ,- ref � �i 7 Chehalis River ^'' r , 0. - _ 1Vewaukum River , V1;I .Ir i, `�'Pe EI / .�''14`". , Napavine '-- ",- - „Y South Fork ) • ` ,\` Chehalis River—.~—d.. fir:., r•' ',-a+� p P E RTE E`T v1 x - ''• .+ Winlock Legend �"�- � ` 0 Upper Chehalis Watershed , f,, \' . ' s -4 ' ,- . " /- •' t! .r.,n, i__ Lewis County Boundary �i��_* -+�-- � �_ •� . INN 100 Year Climate Change Floodplain 1 111 % , ,-„ ' • ' I 1100-yr Effective Floodplain(FEMA) tj *" _ ,,^ ...' planning Area Watercourses ti kilt - "" Vader QPlanningArea N r - -- - ram. 0 2 4 a . -,/ Dote:8/21/2021 �// 1 I .-. - :,- V.: Source-Offce of the Chehalis Basin,FEMA,Lewis County;ESRI Miles J 70 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 6-7. 10-Year Modeled Floodplain. c '' •. 5 r r Skookumchuck 1 River "- It J 40.40 r, . ! r �i Centralia � ! ` `4 ''---. � j.. 17 til Y �.., j1 w L4 •' I �. : Chehalis / • F - -re,j='r -,,,. - Chehalis River� % '" t i ),,„;, ./0 0 J1 . 4.. y ry` I fri. , r ti ! "- 4 Newaukum River ,. y Ct: #` „ .- o � -✓ .•a ; +:; Napavine >r t Pe EII /.�,o�- ,y :; v South Fork ( ' ram} Chehalis River-0 -• `-�. • - 1.;.- r rail A. „, 1, PERTEET -., Winlock Legend �"�" ' '�-�r;•.. ' ,.,-''+ 4 Q Upper Chehalis Watershed ' d;i 1 p ,r.,.„ {, , Lewis County Boundary €. f, j ' ` .►y- _1O Year Modeled Floodplain '�i� ""' =100-yr Effective Floodplain(FEMA) !!T 1�' �Q dt . ' .'4-�*}t: —- Planning Area Watercourses Vadel / �PlanningArea ti .--_ . r� 0 2 4 +��r"'^ Date:B/11/2021 1 t r t 1 .:11j.3 _ Source:Offce of the Chholis Bosco,FEMA,Lew,County,ESRI Miles ' _- - - f 6.5 Frequency Floods are commonly described as having a 10-, 50-, 100-, and 500-year recurrence interval, meaning that floods of these magnitudes have (respectively) a 10-, 2-, 1-, or 0.2-percent chance of occurring in any given year.These measurements reflect statistical averages only; it is possible for two or more rare floods (with a 100-year or higher recurrence interval)to occur within a short time period. Assigning recurrence intervals to historical floods on different rivers can help indicate the intensity of an event over a large area. The rivers and other perennial streams in Lewis County follow an annual cycle, with peak flow from November to February.There have been no documented floods in May,June,July, or August, and only a few floods in March, September, and October.The National Weather Service (2021) provides historical fiver flow data at its gages throughout the watershed. Historical crest data on their website begins in 71 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T 1971 for the Doty gage, 1950 for the Centralia gage and Skookumchuck gage, and 1975 for the Newaukum gage. Figure 6-8 shows which months have the most historical crests according to the National Weather Service. Figure 6-8. Percentage of Historical Crests Occurring in Each Month. Percentage of Historical Crests Ocurring in Each Month 35% 30% 25% '114114 , 20% \ 15% _....__ 10% / _._____._ 5% a _.__._ ..__._._._... j o s. QQ �� ao 0o F P cie< >o 0e Chehalis River at Centralia Chehalis River at Doty Newaukum Skookumchuck Source:NWS,2021 Recent history has shown that Lewis County can expect an average of one episode of minor river flooding each winter. Large, damaging floods typically occur every two to five years, and in several years more than one record setting flood has occurred in one flood season. See Figure 6-9. Figure 6-9. Historical Crests Per Year. Historical Crests Per Year 6 5 I 4 3 1 I 2 II 1 ��r A Ii L A A A 1 I, Iq SIT , 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 Chehalis at Centralia -Chehalis at Doty Newaukum Skookumchuck Source:NWS,2021 72 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 6.6 Severity Flooding in the Chehalis River Basin is increasing in frequency and severity.The largest floods on record have all occurred within the past thirty years.The chances of having the FEMA 100-year flood has increased by 33 percent (Rukelshaus Center, 2014). The FEMA 100-year flood was defined in September 1979, before the largest and most damaging floods occurred in the basin (FEMA, 2006). FEMA will update the FIRM maps in Lewis County; however,the current 100-year flood is based on statistics which do not include the peak floods that occurred in 1996 and 2007, and other floods of record in 1986, 2009, and 2020. FEMA prepared draft updated flood maps in 2010 with a higher discharge than the current maps, but the process stalled. At this time of this report, FEMA is not working on map updates in Lewis County and does not know when map updates may happen (FEMA, 2021d). According to the FEMA Flood Insurance Study(2006),the discharge at the Grand Mound gaging station used to map the 100-year floodplain is 55,000 cfs and the 500-year flood discharge is 70,000 cfs. In comparison with more current modeling updates develop for the Chehalis Basin Strategy and used in this plan, the estimated 100-year flood discharge at Grand Mound is 75,000 cfs.The discharge during the current flood of record in 2007 was 79,100 cfs (WA Ecology, 2017).The climate change models estimate an increase from 26 percent to 50 percent(Mauger, 2021 and McNamara, 2020). See Table 6-2 for a comparison of discharge rates at the Grand Mound gaging station.Additional discharge rates are not provided in this plan as the data is outdated and will change when FEMA updates the county-wide FIRMs. Table 6-2. Discharge rates at the Grand Mound Gaging Station. Data Point Location Discharge(cubic feet/second) FEMA 100-Year Flood (effective floodplain) 56,000 FEMA 500-Year Flood 70,000 1996 Flood Actual 74,800 100-Year Modeled Flood 75,000 2007 Flood Actual (Flood of Record) 79,100 Mid-Range Climate Change 102,200 High End Climate Change 128,600 6.7 Warning Time 6.7.1. Lewis County Flood Warning System After the 2007 flood and formation of the Chehalis River Basin Flood Authority, regional stakeholders led a process to improve the existing flood warning system that was based primarily on the National Weather Service's (NWS)Advanced Hydrologic Prediction System.The result is a robust, publicly accessible,web-based system that provides several sources of information, including rainfall, stream, wind, temperature, and other weather data.The system lacks an automated warning system. Lewis County Emergency Management monitors the system and sends local alters using the "Lewis County Alert" system. 73 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T The current flood warning system website address is: http://www.chehalisriverflood.org/.The site includes several features from more than 250 sensors to help residents be aware of flooding conditions and increase their level preparedness, including: Inundation Mapping Figure 6-10 shows the inundation map for the Chehalis River at Centralia for four flood stages: no flooding(blue), minor flooding (orange), moderate flooding(red), and major flooding(purple).The inundation mapping helps residents and emergency services be better prepared by understanding which areas will flood at different river levels. Figure 6-10. Flood inundation mapping. 4"I Iood Inundation Alai'+ ' flood Inundation Nlup+ .......... (-hr6.lI,Rhrr in Cntnil..WA v......... f'MAW R Rim a('tetnlh.WA w.roor.. l -Tr ..�IM1 Ill I -' .L;44 43 <. ' ..f....> S'.* , e i .-+�.ti.�. .. p :AMA � for• i . • , oiiNEM f _ v ilk f• •' -� i f ` I ( .. : l loud Inundation\lap+ "'',' Flood Inundation Maps ......,., ,.. ('Ytl.M Rim n Cnlr.aa.KA ` w.rotor.. < _Mt j =111 , -' <n l`wv. > 111 , i -. , it 'v . • { p t�. .y -�,, 44 fr i . .• ♦ "� _ for ® µor 1 m�. Stream Alerts Within Lewis County,there are seven gages providing river and stream status and forecast information with alerts (Gages#1-#7 shown on Figure 6-11). Users can sign up to receive an email alert. 74 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 6-11. Gage alert locations within Lewis County. AtcGIS- '020-21 Gage Alert, Open in new Mop Viewer Modify Map S Sign In J Details 88 w:eman', ea Share 0 Print-I Measure .... • 6 About CO Content 4 Legend a Q . T.' a Legend Q 2020-21 Chehalis Basin Gage Alert locations El .�.. ♦1C1-Chohda River Below Thrash En, .n reak(Pa ES) ♦12-Chehala River Near Doty �• it . .2. r ♦13-Newaukum Rover Near Chehalis Wrri y- xdl 'Centralia O14-Chehale River At Centralia ,yen /\15-,Skookumchuck River Al Cantraha ♦16-Skookumchuck River Neer 8ucoda ♦1I Chehalis River Near Grand , -- Cb k 1 Mound I" k3 ♦18 Chehalis Rive,At Porter 7 ♦09-Salsop River Near Setsop •1100,Wynoochee River Near •101 Chehalis River Near Montesano Webcams The flood warning system website provides two webcams for users to visually check river conditions. One of the webcams is in Centralia (Figure 6-12). Figure 6-12. Centralia webcam. Looking upriver at Mellen Street bridge Chehalis Ri.;ei et Cen:raiia,WA a,. a 1i%04 < 2021-05-13 14:00:36 > 75 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 6.7.2 Flood Watch and Warning System The NWS issues flood watches and warnings when forecasts indicate rivers may approach bank-full levels or when other types of localized flooding are possible. When a flood watch is issued,the public should prepare for the possibility of a flood. When a flood warning is issued, the public is advised to stay tuned to a local radio station for further information and be prepared to take quick action if needed.A flood warning means a flood is imminent,generally within 12 hours, or is occurring. Local media typically broadcast NWS watches and warnings and weather apps send notification to cell phones. If a flash flood warning is issued, which indicates that sudden or violent flooding is imminent or occurring,the Emergency Alert Service will alarm on NOAA weather radios and cut into local media broadcasts. Flash flood warnings will also trigger wireless emergency alerts on smart phones. Official thresholds for flood warnings have been established by the National Weather Service on the major rivers within Lewis County are shown in Table 6-3. There are several more stream gages across the county for areas that do not currently have river forecasts or predetermined flood stages.These gages are monitored for situational awareness during flood events. Table 6-3. National Weather Service Flood Stages. Flood Stage in Feet Gage Location Major Flood Minor Flood Flood Stage Action Stage Chehalis River near Doty 324.5 323.5 318 315.5 Chehalis River at Centralia 175.5 172 168.5 166 Chehalis River near Grand Mound 144 142.5 141 138.5 Skookumchuck River at Centralia 191 190 189 187 Newaukum River near Chehalis 205.5 204.5 202.5 200.5 6.8 Secondary Hazards 6.8.1 Landslides Landslides are a common occurrence in Lewis County and the Chehalis Basin. In Lewis County, landslides generally occur along cuts in a hillside, usually along roads or highways. Landslides occur when material on a slope is unable to withstand gravity. Several different triggers can lead to landslides (DNR, 2017): • Heavy rainfall often causes landslides as the water lowers the strength of the material,which makes it less able to withstand the force of gravity (Figure 6-12). • Earthquakes create intense shaking and cause the ground to move which causes material which was stable to be unstable. • Vegetation removal, mining, excavation, and other human activities can weaken the material. • Erosion along the base of a slope from rivers can weaken the materials (Figure 6-13). 76 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 6-13. Water and Landslides. Stable Unstable friction ' downhill downhill >friction The addition of water increases I k weight and reduces �,y a frictionJi, , downhill dvwrhlll �r force fnrce rousts � friCtitarl si:d rV sloGre fnclrvn gravey gravity Stable Unstable high internal strength low internal strength The addition of water can decrease III strength and promotes landslides wet sediment Source:DNR,2017 During the December 2007 storm just west of Pe ElI, a massive debris avalanche along with numerous smaller landslides blocked State Route 6,from Pe ElI to Raymond, isolating 21 households without electricity and water. In addition, State Route 8,just west between Porter and Malone, and State Route 508 near Onalaska were blocked by landslides. In the Chehalis headwaters area,the hardest hit area from the storm, nearly 20 inches of rain was recorded within a 48-hour period, most of that falling within the first 24 hours.The Department of Natural Resources recorded over 1,600 landslides in the Chehalis Basin headwaters during a landslide reconnaissance after the floods (DNR, 2008). Figure 6-14 shows the locations of the recorded landslides in the headwaters of the Chehalis Basin, in the southwest portion of Lewis County. Woody debris and sediment, and material from these landslides clogged channels at bridges, creating temporary dams and causing widespread deposition of logs and debris, especially around the Boistfort valley(Lewis County, 2016). 77 NOVEMBER 2021 1 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 6-14. Recorded Landslides in the Headwaters of the Chehalis River Basin as a result of the 2007 storm. Q. )1 / ITI* Pacific y * I New.tt r F ma.mt va ` IT itO '"co.\ 1 a¢1, Ii.�"�hni A.. J. r Fml:ml �` t.11P 1 111 ''mot •` ,I0u tet r s t1 Flt• ` ,C � *Fil eke efr ...k.1". Ilk**NIINN'1110 A \�p\,�` 10, r — Ir.In)iiii,6 ilk �. .• a , k { J` : " . �F F``° w ,.1,,, * Lewis, \yit:m S% t'ch t.t a•,a, ,i ittt4 .W ;.a .,.' l a F,µ "ry + ti' .y. ♦ •. ' .a a� •` �'.ti HI VI, Fm1:mi \ 11:•t:n `\ tnliil 4,1% lopo rLi . Ili. " x i hi i. .. r/ i( 1 fl�A.ixY' • r F nnit Lk. tr. a�., TJb Ftttl_OtI kvt \ �crutfr '1rA t.'•+4w li�tMr Fan�F. ca.�:+it ,� t.tta � Qi, kl ► r kawY3nt Lama if �yyma F1: i :kku n t� a,,,,.,— �xr \ �G t a N. �, ru F1b V .� �0 1.25 25 5 j:::: ---AMMEMEMONE MINIS {\I NN I I I ttah . / \ tv t % ;L__ S. N Qtr.11ta11.YnwikfnR arrow 1.1140.i ow 1110 kMi .non _- lountaim t7;u,(2wta terrry aLLuw`tam Fib.Intrtaive in ttpprr lC�e![rm m Foraltun basalt Ricer+ Afr tv'2I.Grande Roo&Basalt,upper Roos ow normal mato elk polarity IOW.Vakank racks el Grays River * I.amhll.be OEankkk.Liman Cmic Fumigation111 MO.Caernm Formation bartlt — tautt Ent(I).Marine sedkamentnry mks S bit.totem vokntk tunFal(2ta).M i-Int ik Fmmatian Eek(pe).Pr Ell Vukank Member.Cowbta Fonaatian Source:DNR,2008 Other notable landslides in Lewis County include (Lewis County, 2016): • As a result of the January 7-8, 2009, storm, over 500 landslides initiated in Lewis County, blocking roads and damaging houses. Rainfall totaled over 10 inches between January 7-8, triggering hundreds of debris flows between Morton and Randle. Near Glenoma, when the debris flows reached the valley, they transformed into hyper-concentrated flows, moving across fields, and pirating on Highway 12 and into roads and driveways. • The winter storms of January 29 through March 11, 1999 brought snow, heavy rains, high winds, and landslides. Heavy saturated soils and unstable conditions on the hillside above Kresky Avenue in Chehalis resulted in a large mass land movement. It caused severe damage with repair costs over$100,000 to the Elks Lodge. During this same time frame, Pe Ell had a newly installed water line collapse from another mass land movement. • During February 1996, Lewis County experienced its largest recorded landslide with an estimated 1.5 million cubic yards of debris.The event destroyed a house five miles east of 78 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Glenoma. Landslides blocked State Route 504 in two places by landslides in Kid Valley, and a landslide closed State Route 7 near Mineral Lake for two days. • In 1984, a mudslide shut down the water supply intake to the reservoir of the cities of Centralia and Chehalis. In November 1990 and January 1991, muddy water was observed at the same location. • After heavy rains in November 1994, a mass land movement occurred approximately one-half mile west of Randle between Peters and Silverbrook Roads.An entire portion of a hill near State Route 12 rolled down on to the highway.The slide was about 30 feet high and more than 100 feet wide.The cleanup cost an estimated $1.2 million. 6.8.2 Erosion Erosion is the deterioration and wearing away of riverbanks. Erosion causes issues with infrastructure and private property located along the riverbanks and creates sediment issues downstream.The Chehalis Basin experiences the following types of erosion: • Channel migration is the lateral movement of a river when it naturally meanders through soft, erodible banks. A study of the Chehalis River between Pe Ell and Chehalis found that between 1945-2013 the channel migrated on average between 0.5 to 20 meters annually. • Bank erosion often occurs with heavy flows or high velocity, often along the outside of river bends. Bank erosion also occurs after there is a disruption in flow, such as a logjam,that creates a new flow pattern. • Channel incision is the eroding of the riverbed, lowering the elevation of the river and often disconnecting it from the floodplain (WA Ecology, 2017). 6.8.3 Other Hazards Flooding can create several other secondary hazards beyond landslides and erosion. In 1986, after the closure of the American Crossarm &Conduit Company, a major flood caused improperly stored tanks full of pentachlorophenol (PCP), a carcinogen, as well as creosote and other hazardous chemicals to tip over.The flood contaminated 25 to 30 residential structures and required millions of dollars to clean up. The site eventually became a superfund site, and was delisted in 2020(Yaw, 2020). And in 2007, after the flood waters began receding,fire fighters became busy fighting fires from wet hay spontaneous combusting(Lewis County, 2009a).After hay becomes wet, either from rain,flooding, or other water sources, microbes begin growing in the hay that create chemical reaction that may result in fire.These reactions cause heat which lead to fire (WSU, 2007). 6.9 Future Trends Lewis County is anticipating an additional 10,000 residents by 2040(OFM, 2017). In 1990, Washington State adopted the Growth Management Act, which among other things required Lewis County to establish urban growth boundaries, rural areas, and natural resource lands.The County and all of the cities have adopted plans and development regulations that are currently in compliance with the Growth Management Act. 79 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T The County's and Cities' Comprehensive Plans have adopted goals, objectives, policies, and actions with regards to frequently flooded areas.These plan components strive to steer future trends in development away from increasing flood risks in Lewis County. Lewis County's critical areas regulations regulate how development and redevelopment can safely occur on lands that contain critical areas. Additionally, Lewis County and its cities participate in the NFIP and have adopted flood damage prevention ordinances in response to its requirements. Lewis County has committed to maintaining its good standing under the NFIP through actions identified in this plan. 6.10 Scenario The primary water courses in the planning area flood at regular intervals,generally in response to a succession of intense winter rainstorms. Storm patterns of warm, moist air usually occur between early November and late February. Major roads could be blocked, preventing critical access for many residents and responders. High in-channel flows could cause water courses to scour, possibly washing out roads and creating additional isolation issues. Resources would be stretched thin resulting in delays in repairing and restoring critical facilities and infrastructure.The mapped and identified floodplains in the County are where most impacts from flooding would be concentrated. The Draft SEPA EIS prepared for the Proposed Chehalis River Basin Flood Damage Reduction Project(WA Ecology, 2020) identified mid-century (2030-2060)to late-century(2060 to 2080)flooding impacts in the no action alternative.The no action alternative assumes that large flood control projects will not occur, but existing activities, programs, and trends will continue to occur.The no action alternative evaluates a major flood (38,000 cfs at Ground Mound) and a catastrophic flood (75,100 cfs at Ground Mound, similar to 1996 and 2007 floods).The Draft EIS describe the following scenarios for the no action alternative for a late-century catastrophic flood: • 1-5 at Chambers Way will be under 8.4-feet of floodwater for almost 60 hours. • SR 6 at Boistfort Road will be under 7.5-feet of floodwater for 17 hours. • Several local roads in the Chehalis-Centralia area will be under 2-to 7-feet of water for 27-57 hours. • The Chehalis-Centralia airport will be inundated by 8.2-feet of floodwater. • Fire Station 3 for District 16 will be under 4.5-feet of water. • Valley View Health Center will be under 3.2-feet of water. • Washington Elementary School will be inundated by over 4-feet of water. • Washington State Patrol will be under 3.8-feet of water. • Centralia Police Station will be under 0.23-feet of water. 6.11 Challenges, Gaps, and Issues The planning team has identified challenges, data gaps and issues associated with full identification and understanding of flood hazards in the planning area.These include, but not limited to the following: • The currently available flood hazard mapping for the County does not accurately reflect the true flood risk.A significant amount of modeling data exists in the basin.There are inconsistencies between various results that could result in increased risk. 80 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • There needs to be a sustained effort to continue gathering historical damage data, such as high- water marks on structures and damage reports,to measure the cost-effectiveness of potential mitigation projects. • Ongoing flood hazard mitigation and FCZD operations and maintenance will require funding from multiple sources including the development of local revenue streams. • Existing floodplain-compatible uses such as agricultural and open space need to be maintained. During times of moderate to high growth there is pressure to convert these areas to more intensive uses. • There needs to be a coordinated flood hazard mitigation effort among county jurisdictions affected by flood hazards. • Education for residents in flood hazard areas about flood preparedness and the resources available during and after floods should continue. • There is a lack of consistency in regional flood hazard management policy in the planning area. • As the planning area continues to grow,there will be increased pressures for development in areas subject to flood risk. • Identified floodplain restoration/reconnection opportunities should be implemented to reduce flood risk. • Post-flood disaster response and recovery actions need to be clearly identified. • Current or greater staff capacity is required to maintain the existing level of flood hazard management within the planning area. • Flood hazard management actions require interagency coordination. 81 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 7.0 FLOOD HAZARD EXPOSURE 7.1 Population Population counts of those living in the 100-year FEMA effective floodplain, 100-year modeled floodplain, and 10-year modeled floodplains were generated by analyzing structures in the floodplain. The total planning area population from the 2010 Census was multiplied by the ratio of the number of residential structures in each floodplain to the total number of residential structures. Using this approach,the populations in each floodplain were estimated as follows: • 100-year effective floodplain—5,346 (10.3 percent the planning area population) • 100-year modeled floodplain—8,808(16.9 percent of the planning area population) • 100-year climate change floodplain—12,483 (24.0 percent of the planning area population) • 10-year modeled floodplain—1,909 (3.6 percent of the planning area population) Note that in the unincorporated county and in Pe Ell the modeled floodplains cannot be directly compared to the effective floodplain. In the unincorporated county the model does not include many of the smaller tributary creeks that feed into the Chehalis River,and in Pe Ell the model does not include Stowe Creek. Direct comparisons between the modeled floodplain and the effective floodplain can be made within the Cities of Centralia, Chehalis, and Napavine. Figure 7-1 demonstrates the differences between the 100-year effective floodplain and the modeled floodplain and shows how the FEMA effective floodplain continues upstream of the model at many tributaries.These differences are also shown on the maps in Figures 6-4, 6-5, and 6-6.While many of these areas are very rural and there are not many structures within the floodplain to affect damage estimates,the difference in area is significant. 82 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 7-1. Differences Between Effective and Modeled Floodplain. #70/4 ---....11,,, 41 Chehalis River ' fi : - f'�1 ' %Iii„, 7..-.3,- -- -4k .--/- " . is K rr,14,...,-"7---. i 0-- /A-:1112,0, , ; ..--#%7'9'„, I ` f 4 ~,; ��'� � - _ ChehalisRiver Pe EII �, .r'�" 4 7, fir. /. ale ' r it d r '� �,�r• . /fr/r < P.' . ,. 4 '/ t r i 1 t f ^c.: 00 PERTEET ,, -'° de "-. ' ri i t Legend 11 ,. 4, ry ` ;if' I? '1• CIUpper Chehalis Watershed / •r '/ --or ®Lewis County Boundary 7/ ME100 Year Modeled Floodplain /'`' �,i j ,�� / l•tt ✓ r , �� MN I00-yr Effective Floodplain(FEMA) �. / '4R.. -PlanningArea Watercourses "�j /�� - sA• Planning Area ® _ / err l � 0' .�.2 q ,.�II /!�t / . 'r�,a „� ` Dnte:8/21/2021 . ,,` ,�, 1 0 . Source:Offceof the Chehalis Basin FEMA.Lewis County;ESRI '9I Miles 0 r1 s' • ,.qws '� 7.2 Property 7.2.1 Structures in the Floodplain The Hazus model determined the number and use of the structures within the floodplain.Table 7-1 summarizes the total structures in the area of the 100-year effective floodplain, 100-year modeled floodplain, and 100-year climate change floodplain by municipality, and Table 7-2 summarizes the total area and number of structures in 10-year floodplain by municipality. See Chapter 5.2 for more information on the Hazus model. 83 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Table 7-1.Total Area and Number of Structures in the 100-year Floodplains by Municipality. 100-Year Effective Floodplain Number of Structures Area Residential Commercial Industrial Agriculture Religion Gvmt Education Total (acres) Centralia 1,666 818 88 10 0 5 0 15 936 Chehalis 1,897 238 117 19 0 0 1 8 383 Napavine 134 4 8 1 0 1 0 1 15 Pe Ell 52 17 0 0 0 0 0 1 18 Unincorporated 24,461 849 27 10 0 1 5 16 908 County Total 28,210 1,926 240 40 0 7 6 41 2260 100-Year Modeled Floodplain Number of Structures Area Residential Commercial Industrial Agriculture Religion Gvmt Education Total (acres) Centralia 2,270 2,108 179 32 0 7 1 20 2347 Chehalis 1,852 216 111 17 0 0 1 8 353 Napavine 107 1 1 0 0 0 0 0 2 Pe EII' 39 11 0 0 0 0 0 0 11 Unincorporated 19,759 674 23 9 0 1 4 18 729 County' Total 24,027 3010 314 58 0 8 6 46 3,442 100-Year Climate Change Floodplain Number of Structures Area (acres) Residential Commercial Industrial Agriculture Religion Gvmt Education Total Centralia 2,858 2,963 250 52 0 16 4 23 3,308 Chehalis 1,953 260 130 32 0 1 1 8 432 Napavine 127 1 3 0 0 1 0 1 6 Pe Ell' 44 15 0 0 0 0 0 0 15 Unincorporated County' 21,519 1,122 36 9 0 3 4 21 1,195 Total 26,501 4,361 419 93 0 21 9 53 4,956 1 Area and structure counts within the unincorporated county and Pe Ell cannot be compared to the 100-year effective floodplain.See Section 7.1. 84 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Table 7-2.Total Area and Number of Structures in the 10-year Floodplain by Municipality. 10-Year Modeled Floodplain Number of Structures Area(acres) Residential Commercial Industrial Agriculture Religion Gvmt Education Total Centralia 940 332 54 11 0 2 1 4 404 Chehalis 1,005 74 19 1 0 0 0 2 96 Napavine 49 0 0 0 0 0 0 0 0 Pe Ell' 24 5 0 0 0 0 0 0 5 Unincorporated 13,535 273 2 0 0 0 0 2 277 County' Total 15,553 684 75 12 0 2 1 8 782 1 Area and structure counts within the unincorporated county and Pe Ell cannot be compared to the 100-year effective floodplain.See Section 7.1. 7.2.2 Exposed Value The Hazus model estimated the value of the structure and their content within the floodplain.Table 7-3 summarizes the values in the area of the 100-year effective floodplain, 100-year modeled floodplain, and 100-year climate change floodplain by municipality, and Table 7-2 summarizes the total area and number of structures in 10-year floodplain by municipality. See Chapter 5.2 for more information on the Hazus model. Table 7-3.Total Value of Structures and Content in the 100-year Floodplains by Municipality. 100-Year Effective Floodplain Value Exposed %of Total Structures Contents Total Value Exposed Centralia $433,251,197 $335,039,837 $788,291,034 41% Chehalis $364,182,436 $339,472,350 $703,654,786 37% Napavine $15,993,252 $16,233,098 $32,216,350 2% Pe Ell' $2,321,643 $1,179,743 $3,501,386 0.2% Unincorporated County' $221,823,996 $155,867,212 $377,691,208 19.8% Total $1,037,572,524 $867,782,240 $1,905,354,764 100% 100-Year Modeled Floodplain Value Exposed %of Total Structures Contents Total Value Exposed Centralia $727,534,673 $559,648,659 $1,287,183,332 57.3% Chehalis $293,656,186 $278,742,527 $572,398,712 25.5% Napavine $752,313 $729,758 $1,482,072 0.1% Pe Ell' $1,694,036 $847,018 $2,541,054 0.1% Unincorporated $221,600,130 $157,425,262 $379,025,392 17% County' Total $1,245,237,338 $997,393,224 $2,242,630,562 100% 85 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 100-Year Climate Change Floodplain Value Exposed %of Total Structure Contents Total Value Exposed Centralia $1,080,309,126 $827,984,914 $1,908,294,040 59.9% Chehalis $378,808,275 $372,552,163 $751,360,438 23.5% Napavine $11,817,478 $11,794,923 $23,612,400 0.7% Pe El11 $2,375,447 $1,187,724 $3,563,171 0.1% Unincorporated $300,201,615 $204,019,860 $504,221,474 15.8% Countyl Total $1,773,511,941 $1,417,539,583 $3,191,051,525 100% 1 Structure and content values within the unincorporated county and Pe ElI cannot be compared to the 100-year effective floodplain.See Section 7.1. Table 7-4.Total Value of Structures in the 10-year Floodplain by Municipality. 10-Year Modeled Floodplain Value Exposed %of Total Structure Contents Total Value Exposed Centralia $131,328,644 $100,633,804 $231,962,448 58.3% Chehalis $44,313,476 $37,367,668 $81,681,144 20.5% Napavine $0 $0 $0 0% Pe Ell' $693,340 $346,670 $1,040,010 0.3% Unincorporated Countyl $54,121,530 $29,084,599 $83,206,129 20.9% Total $230,456,990 $167,432,741 $397,889,732 100% 1 Structure and content values within the unincorporated county and Pe ElI cannot be compared to the 100-year effective floodplain.See Section 7.1. 7.2.3 Zoning in the Floodplain Some land uses are more vulnerable to flooding, such as single-family homes,while others are less vulnerable, such as agricultural land or parks.Tables 7-5 through 7-10 show the existing zoning of all areas in the 100-year floodplains and 10-year floodplain, including vacant land and land in public/open space uses. All values were derived from GIS analysis of County data. Table 7-5. Zoning in the Floodplain—City of Chehalis. 100-Year 100-Year 100-Year 10-Year Modeled Effective Floodplain Modeled Floodplain Climate Change Floodplain Zoning Area %of Area %of Area %of Area %of Category (acres) total (acres) total (acres) total (acres) total Commercial 910 49% 870 47% 1383 52% 247 22% Government 591 32% 595 32% 679 14% 333 30% Industrial 278 15% 293 16% 364 14% 180 16% Residential 96 5% 92 5% 237 9% 56 5% Total 1875 100% 1850 100% 2663 100% 1125 100% UGA 297 300 417 73 86 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Table 7-6.Zoning in the Floodplain—City of Centralia. 100-Year 100-Year 100-Year 10-Year Modeled Effective Floodplain Modeled Floodplain Climate Change Floodplain Zoning Area %of Area %of Area %of Area %of Category (acres) total (acres) total (acres) total (acres) total Commercial 263.5 15% 332 14% 590 9% 63 4% Healthcare 14 1% 18 1% 95 1% 6 <1% Industrial 702 41% 174 7% 939 14% 190 12% Open Space 213 12% 457 20% 1030 16% 429 28% Residential 444 26% 1094 46% 3325 51% 776 50% Master Plan 72.3 4% 178 7% 398 17% 77 5% Total 1708 100% 2393 100% 6500 100% 1556 100% UGA 832 979 2228 530 Table 7-7.Zoning in the Floodplain—City of Napavine. 100-Year 100-Year 100-Year 10-Year Modeled Effective Floodplain Modeled Floodplain Climate Change Floodplain Zoning Area %of Area %of Area %of Area %of Category (acres) total (acres) total (acres) total (acres) total Commercial 133 100% 107 100% 230 100% 57 100% Total 133 100% 107 100% 230 100% 57 100% UGA 0 0 0 0 Table 7-8. Zoning in the Floodplain—City of Pe Ell. 100-Year 100-Year 100-Year 10-Year Modeled Effective Floodplain Modeled Floodplainl Climate Change' Floodplainl Zoning Area %of Area %of Area %of Area %of Category (acres) total (acres) total (acres) total (acres) total Residential 52 100% 39 100% 156 89% 28 100% Commercial - - - - 19 11% - - Total 52 100% 39 100% 175 100% 28 100% UGA .4 - - - 1The modeled floodplain does not include Stowe Creek and cannot be directly compared to the effective floodplain.See Section 7.1. 87 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T Table 7-9.Zoning in the Floodplain—Unincorporated County(Chehalis Basin). 100-Year Effective Floodplain 100-Year Modeled Floodplainl Zoning Category Area (acres) %of total Area (acres) %of total Agriculture 10,948 44% 11,506 58% Commercial 73 <1% 200 1% Rural 11,424 46% 6,467 33% Forest 1,585 6% 116 1% Industrial 273 1% 172 1% Parks 26 <1% 53 0% Mineral 535 2% 124 1% Total 24,864 100% 19,710 100% 100-Year Climate Change Floodplainl 10-Year Modeled Floodplainl Zoning Category Area (acres) %of total Area (acres) %of total Agriculture 14,310 57% 8,760 65% Commercial 340 1% 11 <1% Rural 9,695 39% 4,547 34% Forest 3 0% 90 <1% Industrial 317 1% 10 <1% Parks 81 0% 24 <1% Mineral (Mine) 195 1% 108 <1% Total 26,941 100% 13,550 100% 'The modeled floodplain cannot be directly compared to the effective floodplain.See Section 7.1. 7.3 Critical Facilities and Infrastructure 7.3.1 Hazardous Materials Facilities Hazardous material facilities are those that use or store materials that can harm the environment if damaged by a flood. For this assessment, such facilities were identified through the EPA's Toxic Release Inventory(TRI) (EPA, 2021) and other facilities identified by the planning team. Seven business within the Chehalis River Basin have been identified as TRI reporting facilities or other known hazardous material containing facilities.Two businesses are partially in the 100-year floodplain. During a flood event, containers holding these materials can rupture and leak into the surrounding area, having a disastrous effect on the environment as well as residents. 7.3.2 Utilities and Infrastructure It is important to determine who may be at risk if infrastructure is damaged by flooding. Roads or railroads that are blocked or damaged can isolate residents and can prevent access throughout the planning area. Preserving access is particularly important for emergency service providers needing to get to vulnerable populations or to make repairs. Bridges washed out or blocked by floods or debris also can cause isolation. Water and sewer systems can be flooded or backed up, causing health problems. Underground utilities can be damaged. Dikes and levees can fail or be overtopped, inundating the land 88 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T that they protect.The following sections provide more information on specific types of critical infrastructure.Tables 7-10 lists the specific types of infrastructure in the floodplains. Table 7-10. Critical Infrastructure within the floodplain. Communi- Transportation Potable Water Wastewater ity cations Airports Systems Facilities Facilities Facilities Total 100-Year Effective Floodplain Unincorporated 1 - - - 1 2 County Chehalis - - 1 - 1 2 Centralia - - - - - 0 Napavine - - - - - 0 Pe Ell - - - - - 0 100-Year Modeled Floodplain Unincorporated County' 1 - - - - 1 Chehalis - - 1 - - 1 Centralia - - - - - 0 Napavine - - - - - 0 Pe Ell' - - - - - 0 100-Year Climate Change Floodplain Unincorporated County' 1 - - - 1 Chehalis - 2 1 - 1 4 Centralia 2 1 - 1 4 Napavine - - - - - 0 Pe Ell' - - - - 1 1 10-Year Modeled Floodplain Unincorporated County' 1 - - - - 1 Chehalis - - - - - 0 Centralia - - - - - 0 Napavine - - - - - 0 Pe Ell' - - - - - 0 1The effective floodplain cannot be directly compared to the modeled floodplain.See Section 7.1. Roads The following major roads in the planning area pass through the 100-year and/or 500-year floodplain and thus are exposed to flooding. Some of these roads are built above the flood level, and others function as levees to prevent flooding. Still, in severe flood events these roads can be blocked or damaged, preventing access to some areas: • Interstate 5 • US Route 12 • State Route 505 • State Route 507 • State Route 508 • State Route 26 89 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Bridges Flooding events can significantly impact bridges,which provide the only ingress and egress to some neighborhoods.There are 34 locally maintained bridges and 27 state-maintained bridges that are in or cross over the 100-year effective floodplain within the planning area. Water and Sewer Infrastructure Water and sewer systems can be affected by flooding. Floodwaters can back up drainage systems, causing localized flooding. Culverts can be blocked by debris from flood events, also causing localized urban flooding. Floodwaters can get into drinking water supplies, causing contamination. Sewer systems can be backed up, causing wastewater to spill into homes, neighborhoods, rivers, and streams. Dams According to the Washington Department of Ecology's Inventory of Dams Report(WA Ecology, 2020), there are 37 dams in the Chehalis River Basin with Lewis County and 8 dams in Thurston County that would affect Lewis County for a total of 45 dams.Thirty-three of these dams are related to the Transalta coal mining operations. Dam failures can be caused by natural events,such as flooding or an earthquake, but they are predominantly caused by human error such as poor construction, operation, maintenance, or repair. The effects of a dam failure are highly variable, depending on the dam,the amount of water stored behind the dam,the current stream flow,and the size and proximity of the downstream population. There are many effects of a major dam failure: loss of life, destruction of homes and property, damage to roads, bridges, power lines, and other infrastructure, loss of power generation and flood control capabilities, disruption of fish stock and spawning beds, and the erosion of stream and riverbanks. In 1991,the Seminary Hill Reservoir dam owned by the City of Centralia failed due to a landslide that breached the reservoir, causing$3 million in damages and destroying two homes and damaging many others(Lewis County, 2016). Washington State's Downstream Hazard Classification system for dams assigns a hazard rating of"Low," "Significant" or"High"for areas at risk of economic loss and environmental damage should a dam fail. Of the 37 state inventoried dams within Lewis County, one is rated high (1B). Failure of this dam,the Carlisle Lake Dam on the South Fork Newaukum River, could affect a population of 31-300 lives. In Thurston County,the Skookumchuck Dam Hydro Facility is rated high (1A). Failure of this dam would affect more than 300 people, inundate major transportation routes and industries, and have long-term effects on water quality and wildlife. The classification system does not indicate the condition of the dam. Neither of the high hazard dams mentioned above are considered to have deficiencies. One dam in Thurston County,the Kyte Dam on the Skookumchuck River, is listed on the 2018 Dam Safety Legislative Report as having a medium level of deficiency.This dam is rated 2D with 3 people at risk. Lewis County is highly vulnerable to the failure of the Skookumchuck Dam. Due to the status as a high hazard dam, inundation mapping is included in the emergency action plans. Emergency management agencies typically have this data to support emergency response functions, however there can be limitations on the use and distribution of this data due to security concerns. The inundation area mapping is available for the Skookumchuck Dam and was reviewed during this planning process. Figure 7-2 is a graphic from the 2016 Lewis County Multi-Jurisdictional Hazard Mitigation Plan planning process that demonstrates the impact of a dam failure.This information shows that the flood flow will inundate 90 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T most of Centralia and a portion of Chehalis, as well as cause significant impacts in the County. According to the Skookumchuck Dam Inundation Map (Unknown, 2002),flood waters will take approximately four hours to reach Centralia at the Downing Road/SR 507 bridge and cause the water surface to rise over 14-feet. Levees Levees are a basic means of providing flood protection along waterways in regions where development exists or is planned, and in agricultural areas. Levees typically confine floodwaters to the main river channel. Failure of a levee can lead to inundation of surrounding areas. The causes of levee failures are structural failures,foundation failures of underlying soils, and overtopping by flood flows and waves. Contributing factors include poor construction materials, erosion by current and wave action,seepage through or under the levee, burrowing rodents, and improper repairs. Lack of adequate and regular maintenance to correct these problems also contributes to levee failure, including vegetation. Most failures are composites of several of these factors. FEMA accredits levees as providing adequate risk reduction if levee certification and an adopted operation and maintenance plan are adequate.The criteria for which a levee can be accredited are specified in 44 CFR Section 65. Section 65.10 provides the minimum design, operation and maintenance standards levee systems must meet to be recognized as providing protection from the base flood on a Flood Insurance Rate Map. For a levee to be accredited,the owner must provide data and documentation to demonstrate that the levee complies with these requirements. An area impacted by an accredited levee is shown as a moderate-risk area and labeled Zone X on a FIRM.This accreditation affects insurance and building requirements.The NFIP does not require flood insurance for areas protected by accredited levees, although FEMA recommends the purchase of flood insurance in these areas due to the residual risk of flooding from levee failure or overtopping. If a levee is not accredited,the area it protects will still be mapped as a high-risk area (a 100-year floodplain), and the federal mandatory purchase of flood insurance will apply(FEMA, 2012). Even with levee certification and FEMA accreditation,there is a flood risk associated with levees. While levees are designed to reduce risk, even properly maintained levees can fail or be overtopped by large flood events. Levees reduce risk,they do not eliminate it. 91 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 7-2. Skookumchuck Dam Inundation Area. Le 11111111 _ Downing Rd ei$ ,. 17' _ ,ifil t. ... .„. +am r ij IVRdLJ WReynolds Ave �I ll I i z a! 2 ton E Borst Ave , ■■k,rd°E sth$t'�i�M�bn 51 , I fill L;'�• ■�■1� 1 � �I Little Hanalord Rd III1" o` Exit 1 ■�■�■ /1 W,$lsi ■w i■■ a 1111.1111111 W (82 is ■ ��■t'f; o ` ' try �i ft1`e IIIIIIII �I40,4'4,�Sra i.b ill R 4 , I z; 1 Cooke Hlll Rd i *alb f�ie,�� :"�$.I1 .ii 4 it_,I..kit'a . • O'" .s, 1-` gr+¢3.�I ya�� I� ,/ Seminary�iift: al - Exit `. Graf Rd m-• y IS 4, i c8�_' 81 kii c■�Q E sumrra st -.1 N 1`3 f II:■ mS�'�' ' " R n t S l k N > ,. Al Tt < x) A yam'- � 1, � .i i i i i i I I ■ City Limits _ m-m_' Lewis County, Washington 2015 Multi jurisdictional Hazard Mitigation Plan too-yr flood Levecs/rcvct. g 500-yrfl Centralia Facilities & Evacuation Routes EiDam Inundation ° °•'` o. -` dF: Date. July 21,2015 L.h.,f1N SIR;,cr:oio,-vrr Jo. 92 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T In Lewis County, according to the United States Army Corps of Engineers National Levee Database (2021)there are seven levee segments that provide protection against floods within the Chehalis River Basin. Information on these levee segments has been provided in Table 7-11. None of these levee segments are accredited by FEMA. Four of the levees are active in the US Army Corps of Engineers PL 84-99 Program which provides financial support for repairs. Table 7-11. Levee Profiles. Property Value Level of Protection Levee Segment Name Length(feet) Protected (%chance of PL 84-99 exceedance) Status Skookumchuck .81 mi $181 M .02%chance Active Skookumchuck River Levee .51 mi N/A N/A Not Enrolled Salzer Creek Levee .44 mi $3.58 M .02%chance Active Newaukum River Levee .45 mi $16 M N/A Not Enrolled Long Road Levee 1.64 mi $41.6 M 5%chance Active Chehalis-Centralia Airport Levee 2.17 mi $49.3 M .02%chance Active Chehalis River Levee .56 mi N/A N/A Not Enrolled Source:USACE,2021 7.3.3 Critical Facilities Critical facilities provide vital serves to residents every day and may provide necessary support functions during a flood. For example, during a flood schools may provide safe gathering spaces and shelter for those whose homes are impacted, medical facilities provide care to injured people, and fire stations house equipment that is necessary for response. Some facilities are considered critical because of what is located at the facility. For example,facilities with hazardous materials need to be protected from flooding, and assisted living facilities care for residents with limited mobility and may need support if evacuation is necessary. Within the 100-year modeled floodplain, some of the critical facilities that are exposed to flooding include: • Unincorporated County:Adna High School, County Fairgrounds, Curtis, and Adna Post Offices • Centralia: Washington Elementary School, Fire Station 1,Transfer Station • Chehalis: Clinic, Senior Center 93 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Table 7-12. Critical Facilities within the floodplain. Police Schools and Hazardous Other City and Fire Educational Materials Essential Stations Medical Care Total Facilities Facilities Facilities 100-Year Effective Floodplain Unincorporated 2 - 1 4 7 County Chehalis - 2 - - - 2 Centralia - 1 - - - 1 Napavine - - - - - 0 Pe Ell - - - - - 0 100-Year Modeled Floodplain Unincorporated 1 1 2 4 8 County Chehalis - 2 - - - 2 Centralia 1 2 2 - 2 7 Napavine - - - - - 0 Pe Ell - - - - - 0 100-Year Climate Change Floodplain Unincorporated1 1 1 2 - 4 Chehalis 3 5 2 - 10 20 Centralia 2 15 9 - 6 32 Napavine - - - - - 0 Pe Elll - - 1 - - 1 10-Year Modeled Floodplain Unincorporated1 - - - - 3 3 Chehalis - - - - - 0 Centralia 1 - - - 1 2 Napavine - - - - - 0 Pe Elll - - - - - 0 1 The effective floodplain cannot be directly compared to the and modeled floodplain.See Section 7.1. 7.4 Environment Flooding is a natural event and floodplains provide many natural and beneficial functions. Nonetheless, flooding can impact the environment in negative ways, especially when compounded with impacts from human development. Migrating fish can wash into roads or over levees into flooded fields. Pollution from roads, such as oil, and hazardous materials can wash into rivers and streams. During floods these pollutants can settle onto normally dry soils, polluting them for agricultural uses. Human development such as bridge abutments and levees, and logjams from timber harvesting can increase stream bank erosion, causing rivers and streams to migrate into non-natural courses. Many species of mammals, birds, reptiles, amphibians, and fish live in Lewis County in ecosystems that are dependent upon streams, wetlands, and floodplains. Changes in hydrologic conditions can result in a change in the biodiversity of the ecosystem. Wildlife and fish are impacted when plant communities are eliminated or fundamentally altered to reduce suitable habitat. Wildlife populations are limited by shelter, space,food, and water. Since water supply is a major limiting factor for many animals, riparian communities are of special importance. Riparian areas are the zones along the edge of a river or stream that are influenced by or are an influence upon the water body. Human disturbance to riparian areas 94 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T can limit wildlife's access to water, remove breeding or nesting sites, and eliminate suitable areas for rearing young.Wildlife rely on riparian areas and are associated with the flood hazard in the following ways: • Mammals depend upon a supply of water for their existence. Riparian communities have a greater diversity and structure of vegetation than other upland areas. As development occurs in the rural areas, wildlife habitat is lost due to the presence of people or due to nuisance. Beaver dams are often considered a nuisance due to the flooding they cause, but they are an important habitat feature that provide refuge,flood, and nesting areas to several birds and mammals. • A great number of water birds, terrestrial birds, and waterfowl are associated with riparian areas.They swim, dive,feed along the shoreline, or snatch food from above. Lewis County rivers, lakes, and wetlands are important feeding and resting areas for migratory and resident waterfowl. During flood season,waterfowl often use flooded agricultural fields. • Fish habitat throughout the county varies widely based on natural conditions and human influence.The upper reaches of the river have warmer temperatures compared to other headwaters within the basin.This affects habitat for cool water species like salmon and creates favorable habitat for non-native species that prefer warmer water temperatures. When combined with low dissolved oxygen levels,the river becomes a barrier to cool water species and can lead to fish kill. In more urbanized areas, the river channel has been altered and reshaped,woody debris removed, and diversions installed.These alterations all affect habitat in different ways (WA Ecology, 2017). Protection of these biological resources within the floodplains of the planning area is very important to Lewis County. Equipped with planning tools such as WRIA planning, shoreline master program planning, comprehensive planning, critical areas ordinances, and open space planning, Lewis County has been able to establish a diverse inventory of preserve areas that maintain the natural and beneficial functions of the floodplain. 95 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 8.0 FLOOD HAZARD VULNERABILITY 8.1 Population 8.1.1 Vulnerable Populations Persons with disabilities or others with access and functional needs are more likely to have difficulty responding to a flood or other hazard event than the general population. Local government is the first level of response to assist these individuals.Coordination of efforts to meet their access and functional needs is paramount to life safety efforts. It is important for emergency managers to distinguish between functional and medical needs to plan for incidents that require evacuation and sheltering. Knowing the percentage of population with a disability allows emergency management personnel and first responders to have personnel available who can provide services needed by those with access and functional needs.According to the U.S. Census Bureau 2015 American Community Survey estimates, there are about 15,000 individuals in Lewis County with some form of disability, representing 19.4 percent of the county population.Approximately 21 percent(17,307 individuals) are 65 years or older (U.S. Census, 2019). 8.1.2 Public Health and Safety Floods present threats to public health and safety. Floodwater is frequently contaminated by pollutants such as sewage, human and animal feces, pesticides and insecticides,fertilizers, oil, asbestos, and rusting building materials.The following health and safety risks are commonly associated with flood events: • Unsafe food—Floodwaters contain disease-causing bacteria,dirt, oil, human and animal wastes, and farm and industrial chemicals.They carry away whatever lies on the ground and upstream. Their contact with food items, including food crops in agricultural lands, can make that food unsafe to eat and hazardous to human health. Power failures caused by floods damage stored food. Refrigerated and frozen foods are affected during the outage periods and must be carefully monitored and examined prior to consumption. Foods kept inside cardboard, plastic bags,jars, bottles, and paper packaging are subject to disposal if contaminated by floodwaters. Even though the packages may not appear to be wet,they may be unhygienic with mold contamination and deteriorate rapidly. • Contaminated drinking and washing water and poor sanitation—Flooding impairs clean water sources with pollutants and affects sanitary toilets. Direct and indirect contact with the contaminants—whether through direct food intake,vector insects such as flies, unclean hands, or dirty plates and utensils—can result in waterborne infectious disease. Wastewater treatment plants, if flooded and caused to malfunction, can be overloaded with polluted runoff waters and sewage beyond their disposal capacity, resulting in backflows of raw sewage to homes and low- lying grounds. Private wells can be contaminated or damaged severely by floodwaters, while private sewage disposal systems can become a cause of infection and illnesses if they are broken or overflow. Unclean drinking and washing water and sanitation, coupled with lack of adequate sewage treatment, can lead to disease outbreaks, including life-threatening cholera,typhoid, dysentery, and some forms of hepatitis. • Mosquitoes and animals—Prolonged rainfall and floods provide new breeding grounds for mosquitoes—wet areas and stagnant pools—and can lead to an increase in the number of 96 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T mosquito-borne diseases such as West Nile. Rats and other rodents and wild animals also can carry viruses and diseases.The public should avoid such animals and should dispose of dead animals in accordance with guidelines issued by local animal control authorities. • Molds and mildews—Excessive exposure to molds and mildews can cause flood victims— especially those with allergies and asthma—to contract upper respiratory diseases and to trigger cold-like symptoms such as sore throat, watery eyes,wheezing and dizziness. Molds grow in as short a period as 24 to 48 hours in wet and damp areas of buildings and homes that have not been cleaned after flooding, such as water-infiltrated walls,floors, carpets,toilets, and bathrooms.Very small mold spores can be easily inhaled and, in large enough quantities, cause allergic reactions, asthma episodes, and other respiratory problems. Infants, children, elderly people, and pregnant women are considered most vulnerable to mold-induced health problems. • Carbon monoxide poisoning—Carbon monoxide poisoning is as a potential hazard after major floods. Carbon monoxide can be found in combustion fumes, such as those generated by small gasoline engines, stoves, generators, lanterns, and gas ranges, or by burning charcoal or wood. In the event of power outages following floods, flood victims tend to use alternative sources of fuels for heating, cooling, or cooking inside enclosed or partly enclosed houses, garages, or buildings without an adequate level of air ventilation. Carbon monoxide builds up from these sources and poisons the people and animals inside. • Hazards when reentering and cleaning flooded homes and buildings—Flooded buildings can pose health hazards after floodwaters recede. Electrical power systems can become hazardous. People should avoid turning on or off the main power while standing in floodwater. Gas leaks from pipelines or propane tanks can trigger explosion when entering and cleaning damaged buildings or working to restore utility service. Flood debris—such as broken bottles, wood, stones, and walls—may cause wounds and injuries when cleaning damaged buildings. Containers of hazardous chemicals, including pesticides, insecticides,fertilizers, car batteries, propane tanks and other industrial chemicals, may be hidden or buried under flood debris. A health hazard can also occur when hazardous dust and mold in ducts, fans and ventilators of air- conditioning and heating equipment are circulated through a building and inhaled by those engaged in cleanup. • Mental stress and fatigue—Exposure to extreme disaster events can cause psychological distress. Having experienced a devastating flood, seen loved ones lost or injured, and homes damaged or destroyed,flood victims can experience long-term psychological impact.The expense and effort required to repair flood-damaged homes places severe financial and psychological burdens on the people affected, in particular the unprepared and uninsured. Post- flood recovery—especially when prolonged—can cause anxiety, anger, depression, lethargy, hyperactivity, sleeplessness, and, in an extreme case,suicide. Behavior changes may also occur in children.There is also a long-term concern among the affected that their homes can be flooded again in the future. Current loss estimation models such as Hazus are not equipped to measure public health impacts.The best level of mitigation for these impacts is to be aware that they can occur, educate the public on prevention, and be prepared to deal with these vulnerabilities in responding to flood events. 97 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Table 8-1. Number of Persons Displaced or Requiring Shelter. 100-Year Effective Flood 100-Year Modeled Flood' Persons Requiring Persons Requiring Displaced Displaced Short-Term Short-Term Persons Shelter2 Persons Shelter2 Centralia 838 42 3112 160 Chehalis 316 13 326 13 Napavine 7 0 1 0 PeEII3 3 0 3 0 Unincorporated 322 8 634 23 County3 Total 1,546 63 4,076 195 100-Year Climate Change Flood' 10-Year Modeled Flood' Persons Persons Displaced Requiring Short- Displaced Requiring Short- Persons Term Shelter Persons Term Shelter2 Centralia 5531 341 309 15 Chehalis 412 16 79 1 Napavine 2 0 0 0 Pe EII3 5 0 1 0 Unincorporated County3 1,122 54 139 2 Total 7,072 410 528 18 1 Results shown are not precise but are estimates of needs that may occur as the result of the modeled flood. 2 The number of persons requiring publicly provided shelter is less than the number of displaced persons because not all households will require public assistance to find short-term shelter. 3 Number of persons within the unincorporated county and Pe Ell in the modeled floodplains cannot be compared to the 100- year effective floodplain.See Section 7.1. Note:Sources of data used in Hazus modeling are described in Section 5. 8.2 Property 8.2.1 Loss Estimates Hazus calculates flood losses to structures based on flooding depth and structure type. Using historical flood insurance claim data, Hazus estimates the percentage of damage to structures and their contents by applying established damage functions to an inventory. For this analysis local data on facilities was used instead of the default inventory data provided with Hazus.The results of the analyses for the scenario flood events are summarized in Tables 8-2 and 8-3. 98 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Table 8-2. Loss Estimates for 100-Year Flood Events. 100-Year Effective Flood Structures Estimated Loss Associated with Flood %of Total Impacted/ Structure Contents Total Replacement Cost Centralia 375 $15,369,799 $18,707,084 $34,076,883 13.1% Chehalis 275 $40,078,283 $120,759,167 $160,837,450 61.5% Napavine 8 $240,071 $1,704,915 $1,944,986 0.7% Pe EII2 8 $171,358 $110,982 $282,340 0.1% Unincorporated 498 $29,968 370 $34,299,083 $64,267,453 24.6% County2 ' Total 1,164 $85,827,833 $175,581,230 $261,409,113 100% 100-Year Modeled Flood Structures Estimated Loss Associated with Flood %of Total Impacted/ Structure Contents Total Replacement Cost Centralia 1,573 $41,757,447 $68,605,521 $110,362,968 32% Chehalis 300 $39,522,197 $118,729,404 $158,251,600 47% Napavine 1 $3,793 $49,304 $53,096 <0.01% Pe EII2 7 $194,279 $104,382 $298,661 1% Unincorporated o County2 629 $34,500,641 $32,843,798 $67,344,440 20% Total 2,510 $115,978,356 $220,332,409 $336,310,766 100% 100-Year Climate Change Flood Structures Estimated Loss Associated with Flood %of Total Impacted/ Structure Contents Total Replacement Cost Centralia 2,501 $17,427,023 $186,320,558 $293,747,580 44% Chehalis 390 $65,807,994 $187,286,018 $253,094,012 37.8% Napavine 5 $140,551 $690,788 $831,338 0.1% Pe EII2 9 $372,452 $181,590 $554,042 0.1% Unincorporated 985 $58,515,764 $62,213,173 $120,728,936 18% County2 Total 3,900 $232,263,783 $426,692,126 $668,955,909 100% 'Impacted structures are those with finished floor elevations below the Hazus-estimated 100-year water surface elevation for each flood event.These structures are the most likely to receive damage in a 100-year flood event. z The values within the modeled floodplain cannot be compared to the 100-year effective floodplain.See Section 7.1. Notes:Values in this table are only for purposes of comparison among results.See Section 5 for a discussion of data limitations. Sources of data used in Hazus modeling are described in Section 5. 99 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Table 8-3. Loss Estimates for 10-Year Modeled Flood Event. 10-Year Modeled Flood Structures Estimated Loss Associated with Flood %of Total Impactedl Structure Contents Total Replacement Cost Centralia 225 $4,696,200 $5,143,907 $9,840,106 30% Chehalis 61 $2,830,179 $5,243,741 $8,073,920 24.2% Napavine 0 $0 $0 $0 0% Pe Ell 2 $27,315 $16,799 $44,114 0.1% Unincorporated 189 $9,780,593 $5,351,440 $15,132,033 45.7% County Total 477 $17,334,287 $15,755,887 $33,090,174 100% 1 Impacted structures are those with finished floor elevations below the Hazus-estimated 10-year modeled water surface elevation.These structures are the most likely to receive damage in a 10-year modeled flood event. 2 The values within the modeled floodplain cannot be compared to the 100-year effective floodplain.See Section 7.1. Notes:Values in this table are only for purposes of comparison among results.See Section 5 for a discussion of data limitations. Sources of data used in Hazus modeling are described in Section 5. 8.2.2 National Flood Insurance Program Table 8-5 lists flood insurance statistics that help identify vulnerability in the planning area. Five planning area communities participate in the NFIP, with 1,636 flood insurance policies providing over$432.6 million in coverage (this includes portions of the unincorporated county outside of the Chehalis River Basin).According to FEMA statistics, within the planning area 1,872 flood insurance claims were paid between January 1, 1978, and May 24, 2021,for a total of almost$77 million, averaging over$41,000 per claim. Not all structures within the special flood hazard area (SFHA, also known as the 100-year floodplain) are covered by flood insurance. Properties constructed after a FIRM has been adopted are eligible for reduced flood insurance rates. Such structures are less vulnerable to flooding because they were constructed after regulations and codes were adopted to decrease vulnerability. Structures built before a FIRM is adopted are more vulnerable to flooding because they do not meet current codes or are located in hazardous areas.The first FIRMs in the planning area were available in 1980. The following information related to flood insurance statistics is relevant for understanding and reducing flood risk in the planning area: • The uptake of flood insurance within Lewis County(county-wide) is below average.According to FEMA, only 22 percent of residential structures within the 100-year floodplain have a flood insurance policy.According to FEMA, as of July 31, 2019,about 28 percent of single-family homes in special flood hazard areas are covered by flood insurance nationwide (FEMA, 2021c). This rate is referred to as the penetration rate.See Table 8-5 for city estimates. • In Centralia,the amount of insurance coverage in force represents approximately 20 percent of the total value of the assets exposed within the SFHA (estimated buildings and contents). In Chehalis,the amount of insurance coverage represents approximately 9 percent of the total value. • The percentage of policies and claims outside a mapped floodplain confirms that not all the flood risk in the planning area is reflected in current mapping. Based on information from FEMA 100 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T (FEMA, 2021c), 33 percent of policies are for structures outside the SFHA. In Chehalis, 14 percent of policies are for structures outside the SFHA. In the unincorporated county, 46 percent of policies are for structures outside the SFHA(county-wide).Table 8-6 details the location of paid flood claims per jurisdiction. Table 8-4. Flood Insurance Statistics for Lewis County. Date of Entry #of Flood Claims, Value of Claims Total Total Annual Initial FIRM Insurance Policies 11/1978 to paid,11/1978 to Effective Date as of 5/21/2021 Coverage Premium 5/21/2021 5/21/2021 Centralia 6/1/1982 574 $149,682,900 $580,347 672 $26,053,865 Chehalis 5/1/1980 205 $64,844,800 $364,114 448 $28,216,898 Napavine 5/19/2017 2 $850,000 $1,363 0 $0 Pe Ell 3/4/1980 5 $1,137,100 $3,511 1 $37,771 Unincorporated 12/15/1981 850 $216,132,100 $703,068 660 $22,642,061 County' Total 1,636 $432,646,900 $1,652,403 1,781 $76,950,595 'Values reflect all of Lewis County,including areas outside of the Chehalis River Basin. Source:FEMA,2021c Table 8-5. Estimated Residential Penetration Rate within Cities. Number of Number of Residential Residential Number of Residential Total Number Penetration Policies outside 100- Structures in 100- Policies in 100- of Residential Year Effective Year Effective Rate Year Effective Policies Floodplain' Floodplain Floodplain Centralia 818 331 40% 170 501 Chehalis 238 117 49% 26 143 Napavine 4 0 0% 1 1 Pe Ell 17 2 12% 3 5 1 Number of structures in floodplain is an estimate provided by Hazus. Source:FEMA,2021c. Table 8-6. Flood Insurance Claims with Payment beginning 11/1978. A Zones A Zones B,C,X Zones Jurisdiction Percentage of Claims (with BFE or (outside of Unknown outside the 100-Year (without BFE) Total depths) floodplain) Effective Floodplain Centralia 13 545 114 0 672 17% Chehalis 2 408 29 9 448 6.5% Napavine 0 0 0 0 0 0% Pe Ell 1 0 0 0 1 0% Unincorporated 44 449 120 47 660 18% County' Zone Total 72 1,402 263 16 1,176 22% 'Values reflect all unincorporated Lewis County,including areas outside of the Chehalis River Basin. Source:FEMA,2021c. 101 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 8.2.4 Repetitive Loss A repetitive loss property is defined by FEMA as an NFIP-insured property that has experienced two paid losses in excess of$1,000 within any rolling 10-year period. A severe repetitive loss property is defined by FEMA as an NFIP-insured property has experienced either: • Four or more paid losses in excess of$5,000, • Two to three or more paid losses that equal or exceed the current value of the insured property. Repetitive loss properties make up only one to percent of flood insurance policies in force nationally,yet they account for 30 percent of the nation's flood insurance claim payments. In 2004, FEMA reported that the NFIP's 112,540 repetitive loss structures had made 314,640 claims costing$5.17 billion in flood insurance payments and that numerous other flood-prone structures remain in the floodplain at high risk.The government has instituted programs encouraging communities to identify and mitigate the causes of repetitive losses.A report on repetitive losses by the National Wildlife Federation found that 20 percent of these properties are located outside of the mapped 100-year floodplain.The key identifiers for repetitive loss properties are the existence of flood insurance policies and claims paid by the policies (King, 2005). FEMA-sponsored programs, such as the CRS, require participating communities to identify repetitive loss areas. A repetitive loss area is the portion of a floodplain holding structures that FEMA has identified as meeting the definition of repetitive loss. Identifying repetitive loss areas helps to identify structures that are at risk but are not on FEMA's list of repetitive loss structures because no flood insurance policy was in force at the time of loss. Repetitive loss area maps are included in Figures 8-1 and 8-2.The information shown on the maps is limited due to federal privacy laws. This analysis uses information from the 2014 Repetitive Loss Strategy(French and Associates, 2014). Due to privacy laws,the FEMA provided information does not include location data and was not able to be reviewed for accuracy.The breakdown of the properties by jurisdiction is shown in Table 8-7. Table 8-7. Repetitive Loss Properties as of May 21,2021. Total Repetitive Severe Repetitive Unmitigated Areas Buildings Loss Properties Loss Properties Properties Centralia 64 6 31 8 760 Chehalis 65 9 47 8 130 Napavine 0 0 0 0 0 Pe Ell 0 0 0 0 0 Unincorporated 54 3 27 15 165 County Total 183 18 105 31 1055 Source:French and Associates,2014 102 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 8-1. Lewis County Repetitive Loss Areas. NFIP CRS 2018 - Repetitive Loss Areas I -(L''� / __SentraHa 1 r,• i Chehalis 19 ,,- ti y k�-_. j 4 ,Ls 7,Packwood �� 7-7 N�}8pa`�F(" Randle Peen _L'f ;m = .'\ Winlak ��1 _ •.Moss if -jrf -''-'� v✓ I ,_V,adoer; o } �-). Map Book Page Index 103 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T Figure 8-2. Chehalis Repetitive Loss Areas. �,�r t -- 7 "4 ,7 �,�", 1 NbRTH dA >; - ,� 4 fy ..J HL�O r f• �i sl e' 9�, .I;) 1 �r-� i' "it 4y 0 `�°•. I W E J L•rr ' ;.od O �rwu 02 , ! S • I�arlj + I CHEHALIS ' N ,,. QEk RO _ _______ NOS : •.. . 1 . � _,_ ,t tei ilil ..-w 41,S VOA . • " "—.7 or �( �.., -10) .t, " 'a •r-� 0E." ,,, �, 74. „,. 4 aFE�� / \_ `7 /D r• L`, .. G r (-t lc t. CIS ¢ , � ® a • i lO -.0 L._.dri . '--.' ' 'N.d.71.ni • .., e us ' • ,, '.• p'mysrru • ', i OA a Le `, # ' N\ _ co , -i---- ...t. "e. , 0 . ir 1' NE A, f{UM 7 �'=*:3 +' 9s . - .- .._._ :... ter" (hehdlvs :: -, -. T . ----t Repetitive Loss Area \ \/, . ---- cityLimits ti' Hew»t. ao ._ I 10 1 Mile \ y� ��r• 12'. 4 104 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 8.3 Critical Facilities and Infrastructure The Draft SEPA EIS for the Proposed Chehalis River Basin Flood Damage Reduction Project,Appendix I Public Services and Utilities Disciple Report, evaluated the effects of flooding on several critical facilities within Lewis County.The Draft SEPA EIS identified mid-century (2030-2060) and late-century(2060 to 2080)flooding impacts in the no action alternative.The no action alternative assumes that large flood control projects will not occur, but existing activities, programs, and trends will continue to occur.The no action alternative evaluates a major flood (38,000 cfs at Ground Mound) and a catastrophic flood (75,100 cfs at Ground Mound,similar to 1996 and 2007 floods), with flooding increases related to climate change incorporated.The Draft EIS describe the following impacts for a late-century catastrophic flood to vulnerable critical infrastructure, assuming no flood control projects occur: • 1-5 at Chambers Way will be under 8.4-feet of floodwater for almost 60 hours. • SR 6 at Boistfort Road will be under 7.5-feet of floodwater for 17 hours. • Several local roads in the Chehalis-Centralia area will be under 2-to 7-feet of water for 27-57 hours. • The Chehalis-Centralia airport will be inundated by 8.2-feet of floodwater. The Draft SEPA EIS also describes the impact of flooding on specific critical facilities as shown in Table 8- 8. Table 8-8.Vulnerable Critical Facilities(Catastrophic Flood). Feet of Flood Water Facility Mid-Century Late Century Centralia Police Station 0.0 0.23 Washington State Patrol 2.26 3.79 Fire Station 3 District 16 2.52 4.57 Fire Station 1 Riverside Fire Authority .33 1.03 Veterans Memorial Museum 0.76 1.21 Chehalis-Centralis Railroad and Museum 0.58 1.03 Valley View Health Center 1.94 3.29 KCED-FM 0.24 0.93 KITI-AM 6.19 7.53 KELA-AM 6.95 8.29 Source:Draft SEPA EIS,Appendix I(Ecology,2020) 8.4 Environment The environment vulnerable to the flood hazard is the same as the environment exposed to the hazard. The principle environmental impact from flood is the loss of aquatic habitat. One possible measure of environmental impacts from flooding is the amount of debris that that would be generated by each scenario flood event. Hazus includes a debris estimation component.These estimates can provide local governments information on the potential exposure to debris carried by flood water as well as estimates useful for planning for recovery.The Hazus debris estimates for each of the scenario flood events are shown in Table 8-9. 105 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE ET Table 8-9. Estimated Flood-Caused Debris. Debris to Be Removed(tons)1 100-Year 100-Year 100-Year 10-Year Modeled Effective Modeled Flood Climate Change Flood Flood Centralia 5,550 7,611 16,063 1,609 Chehalis 2,277 2,029 3,165 665 Napavine 0 0 0 0 Pe EII2 123 147 207 70 Unincorporated County2 6,141 10,178 13,855 3,491 Total 14,091 19,965 33,290 5,835 1 The Hazus flood debris model focuses on building-related debris and does not address contents removal or additional debris loads such as vegetation and sediment. 2 The values within the modeled floodplain cannot be compared to the 100-year effective floodplain.See Section 7.1. 106 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 9.0 CLIMATE CHANGE CONSIDERATIONS FOR FLOOD HAZARD MANAGEMENT This chapter presents an overview of current understandings of how climate change will affect Lewis County and implications for flood hazard management. Information on climate change is continually updated, and the information presented here is a snapshot of the best available information at the time this document was written. 9.1 What Is Climate Change? Climate, consisting of patterns of temperature, precipitation, humidity, wind, and seasons, plays a fundamental role in shaping natural ecosystems and the human economies and cultures that depend on them. "Climate change" refers to changes in these patterns over a long period of time. Worldwide, average temperatures have increased 2.1°F since 1880(NASA, 2021). Although this change may seem small, it can lead to large changes in climate and weather. The warming trend and its related impacts are caused by increasing concentrations of carbon dioxide and other greenhouse gases in the earth's atmosphere. Greenhouse gases are gases that trap heat in the atmosphere, resulting in a warming effect. Carbon dioxide is the most commonly known greenhouse gas; however, methane, nitrous oxide and fluorinated gases also contribute to warming. Emissions of these gases come from a variety of sources, such as the combustion of fossil fuels, industrial production, changes in land use, and volcanic eruptions. According to the U.S. Environmental Protection Agency(EPA), carbon dioxide concentrations measured about 280 parts per million (ppm) before the industrial era began in the late 1700s and have risen 43 percent since then, reaching 416 ppm in 2021 (US EPA, 2021) (see Figure 9-1). In addition,the concentration of methane has almost doubled, and nitrous oxide is being measured at a record high of 328 parts per billion (ppb) (US EPA, 2021). Scientists are able to place this rise in carbon dioxide in a longer historical context through the measurement of carbon dioxide in ice cores. According to these records, carbon dioxide concentrations in the atmosphere are the highest that they have been in 650,000 years (NASA, 2021).There is broad scientific consensus (95 percent probability)that climate-warming trends are very likely due to human activities (NASA, 2021). Unless emissions of greenhouse gases are substantially reduced,this warming trend and its associated impacts are expected to continue. Climate change will affect the people, property, economy,and ecosystems of Lewis County in a variety of ways. Its impacts are most frequently associated with negative consequences and increased risk, such as increased flooding or increased heat-related public health concerns.The most important effect for the development of this plan is that climate change is expected to have a measurable impact on the occurrence and severity of flooding and flood-related hazards.This chapter summarizes current understandings about climate change to provide a context for the recommendation and implementation of flood hazard mitigation measures in Lewis County. 107 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 9-1. Carbon Dioxide Concentrations Over Time. Global Atmospheric Concentrations of Carbon Dioxide Over Time 800,000 BCE to 2015 CE 1950 to 2015 CE E 450 0. a 400 0 350 r --- �+ 10 C 250 1\411h: A 200 \tr\ovrAit 150 .__- =p 100 O 50 V 0 -800,000 -600,000 -400,000 -200,000 0 1950 1960 1970 1980 1990 2000 2010 2020 Year (negative values= BCE) Year Data source:Compilation of 10 underlying datasets.See www.epa.gov/climate-indicators for specific information. For more information,visit U.S.EPA's"Climate Change Indicators in the United States"at www.epa.gov/climate-indicators. 9.2 How Climate Change Affects Flood Hazard Management An essential aspect of flood hazard management is predicting the likelihood of flooding in a planning area.Typically, predictions are based on statistical projections from records of past events.This approach assumes that the likelihood of flood events remains essentially unchanged over time.Thus, averages based on the past frequencies of floods are used to estimate future frequencies: if a river has flooded an average of once every five years for the past 100 years,then it can be expected to continue to flood an average of once every five years. But the assumption that future flooding behavior will be equivalent to past behavior is not valid if climate conditions are changing. Climate involves not only average temperature and precipitation but also the frequency and intensity of extreme weather events.The frequency of flooding will not remain constant if broad precipitation patterns change over time.While predicting changes in flood events under a changing climate is difficult, understanding vulnerabilities to potential changes is a critical part of estimating future climate change impacts on human health, society, and the environment. For this reason, an understanding of climate change is pertinent to flood hazard management activities. Information about how climate patterns are changing provides insight on the reliability of future flooding projections used in mitigation analysis. 108 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 9.3 Current Indications and Observed Changes 9.3.1 Observed Global Changes The major scientific agencies of the United States and the world—including the National Aeronautics and Space Administration (NASA),the National Oceanic and Atmospheric Administration (NOAA) and the Intergovernmental Panel on Climate Change (IPCC)—agree that climate change is occurring. Multiple temperature records from all over the world have shown a warming trend, and the IPCC has stated that the warming of the climate system is unequivocal (IPCC, 2014). Of the 19 warmest years since 1880, all but one (1998) occurred since 2000, and 2016 and 2020 tied for the warmest years on record (NASA, 2021). Worldwide, average temperatures have increased 2.12F since 1880 (NASA, 2021). Rising global temperatures have been accompanied by other changes in weather and climate. Many places have experienced changes in rainfall resulting in more intense rain, as well as more frequent and severe heat waves (IPCC, 2014).The planet's oceans and glaciers have also experienced changes:oceans are warming and becoming more acidic, ice caps are melting, and sea levels are rising (NASA, 2021). Global sea level has risen nearly seven inches in the last 100 years (NASA, 2021).This has already put some coastal homes, beaches, roads, bridges, and wildlife at risk. NASA currently maintains information on the vital signs of the planet. At the time of the development of this plan,the following trends and status of these signs are as follows(NASA, 2021): • Carbon Dioxide—Increasing trend, currently at 416 parts per million • Global Temperature—Increasing trend, increase of 2.1 degrees Fahrenheit since 1880 • Arctic Ice Minimum—Decreasing trend, 13.1 percent per decade • Land Ice—Decreasing trend,428 billion metric tons per year • Sea Level—Increasing trend, 3.3 millimeters (0.04 inches) per year 9.3.2 Observed Changes in the Pacific Northwest In the Pacific Northwest average annual temperatures increased approximately 1.3 degrees Fahrenheit between 1895 and 2011 (Mote et al., 2014).This has corresponded with a lengthening of the frost-free season and a higher incidence of nighttime high heat events (Dalton, Mote and Snover, 2013). In addition to these temperature related changes, several water-related impacts have been observed (Mote et al., 2014): • Average snowpack—In the Cascade mountains area, average snowpack on April 1 has decreased about 20 percent since 1950. • Snowmelt timing—Spring snowmelt is occurring as much as 30 days earlier in some locations. • Streamflow timing—Streamflow levels and timing have shifted as late winter and early spring stream flows have increased and summer flows have decreased. Like the rest of the western United States,the number and extent of wildfires in the Pacific Northwest have increased since the 1970s.This is believed to have been influenced by the onset of warmer and drier climatic conditions as well as the onslaught of pest infestations, such as mountain pine beetles, fueled at least in part by heat and drought stress(Mote et al., 2014). 109 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 9.4 Future Impacts 9.4.1 Global Projections Scientists project that Earth's average surface temperature will continue to rise between 0.52F and 8.62F by 2100(IPCC, 2014). Some research has concluded that every increase of 22F in average global average temperature can have the following impacts(NRC, 2011): • 3 to 10 percent increases in the amount of rain falling during the heaviest precipitation events, which can increase flooding risks. • 5 to 10 percent decreases in stream flow in some river basins. Although not a concern in Lewis County,the amount of sea level rise expected to occur as a result of climate change will increase the risk of coastal flooding for millions to hundreds of millions of people around the world, many of whom would have to permanently leave their homes (IPCC, 2014). By 2100, sea level is expected to rise another 1 to 4 feet,with an uncertainty range of 0.66 to 6.6 feet(Melillo et al., 2014). 9.4.2 Projections and Potential Impacts for the Pacific Northwest In the Pacific Northwest average annual temperatures are expected to continue to rise by 3.32F to 9.72F by the end of the century(Mote et al., 2014). It is anticipated that these changes will be most dramatic in the summer months. Projected precipitation changes in the region are ambiguous. Some models indicate that an 11 percent decrease in annual average precipitation will occur by mid-century,while other models project an increase of 12 percent for the same time period (Mote et al., 2014).The distribution of precipitation over the seasons is also uncertain, although there is some agreement amongst the models that summer precipitation is likely to decrease (Mote et al., 2014).These changes can have wider implications for stream flow and the incidence of drought and wildfires. Projections for water-related impacts in the region are as follows(Mote et al., 2014): • Snowmelt timing—By 2050, snowmelt is projected to shift three to four weeks earlier than the 20th century average. • Stream flow levels—Summer stream flows are expected to be substantially diminished. • Flood risk—Flood risk is expected to increase most in mixed basin watersheds (those with both rainfall and snowmelt related runoffs) and remain largely unchanged in snow dominated systems. • Heavy precipitation events—It is unclear if there will be an overall increase in heavy precipitation events, but when averaged over the region models indicate that the number of days with more than one inch of precipitation is likely to increase by approximately 13 percent by mid-century. If such increases do occur,they could impact flooding in both mixed and rain- dominant systems, as well as contribute to localized flooding due to overwhelmed storm water management systems. Water-related impacts are expected to contribute to an increased risk of wildfire in the region as water deficits stress trees and increase vulnerability to both insect infestation and combustion (Mote et al., 2014).The average annual area burned by wildfire in the region may quadruple from the last century to two million acres by 2080 (Mote et al., 2014). 110 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 9.4.3 Projections and Potential Impacts for the Chehalis River Basin In 2014,the Climate Impact Group at the University of Washington released a report titled Effect of Climate Change on the Hydrology of the Chehalis Basin (Mauger, et. al, 2016).The report supports the ongoing work to reduce the risk and damage from flooding throughout the river basin.The report found that: • Winter precipitation is projected to increase, while summer precipitation decreases. • Peak streamfiow is projected to increase. • Annual temperature increases are projected to increase. • Sea levels are projected to increase by another two feet along the Pacific coastline. In 2019, the Office of the Chehalis Basin developed a climate change 100-year flood model using information from the University of Washington Climate Impacts Group.The data estimated a 26 percent increase in flood discharge for a late century flood (approximately the year 2080).The depth grid and boundary from the 2019 model was used for the analysis of this plan. In 2020,the model was updated using new data from the Climate Impacts Group.This data showed a substantial increase of 40-65 percent in flood discharge, averaging at about 50% basinwide (Mauger, 2021). Currently,the 2019 model is being considered the "mid-range" projections and the updated 2020 data is considered the "high-end" projections. Figure 9-2 illustrates the forecast changes in flooding for the mid-range climate change projection.The red areas show the increase in area compared to the modeled 100-year floodplain. In some areas,the boundaries for the two floodplains are in the same location. In these areas,the floodwaters have reached the extent they can spread and instead of spreading farther the floodwaters get deeper.The high-end projection will cause an even greater area to be subject to flooding and other areas to be much deeper. 111 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PERTEET Figure 9-2. Mid-Range Climate Change Projections. ..�- ' •• -. ,. r i, ! /•.411.44, d 1. '�.��.-af ..:. ,.... ,_... ,° rLy f - Vim 6- - ar x •. • { . ,.. I*2 '". t Centralia&, ?ph ' G' ', , ‘,� 001 Sul t s .._' '1` '`` Cheh"alis l Chehalis River~ % Cat * = f i O ` ,c t e v aukuar River ` Vlibt t" / ))d• r-eg- i'r/.; /,.• g "` r/= L`'�t'+ South Fork Napavine PERTEET -I Pe Ell '' 0►;I ;.'"~{= Chehalis River c'- 4- ,f .i// > Legend ..r 1771>,q,_ .01' f~' ' f - '✓%'- cmLewis County Boundary 1114 e-Af .. ., - I if Planning Area Watercourses ,' f' .. '•,-��. , *4.4`r .� Planning Area r �j1 .� z' �.r r,. : . -- Modeled 100 Year Floodplain .M , d, ,..�- m Modeled 100-Year Climate Change Floodplain 0" / .�1,, f j QCities / �/ ,J/� s•/ , ,+..- -' .4 .t 0 2 $ t �% , 4 •j`{ , " p Dote.8/22'2021 1 , t ( 4 ,y y„ /►v- Source:Offce of the Chehalis Basin,FEMA,Lewis County;ESRI Miles , '1 - ...� I 9.5 Impacts on Flood-Related Hazards 9.5.1 Flood Use of historical hydrologic data has long been the standard of practice for designing and operating water supply and flood protection projects. For example, historical data are used for flood forecasting models and to forecast snowmelt runoff for water supply.This method of forecasting assumes that the climate of the future will be similar to that of the period of historical record. However,the hydrologic record cannot be used to predict changes in frequency and severity of extreme climate events such as floods. Going forward, model calibration or statistical relation development must happen more frequently, new forecast-based tools must be developed, and a standard of practice that explicitly considers climate change must be adopted. Climate change is already impacting water resources, and resource managers have observed the following: • Historical hydrologic patterns can no longer be solely relied upon to forecast future conditions. 112 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T • Precipitation and runoff patterns are changing, increasing the uncertainty for water supply and quality,flood management and ecosystem functions. • Extreme climatic events will become more frequent, necessitating improvement in flood protection, drought preparedness and emergency response. As hydrology changes, what is currently considered a 100-year flood (one-percent annual chance) may strike more often, leaving many communities at greater risk. Planners will need to factor a new level of safety into the design, operation, and regulation of flood protection facilities such as dams, bypass channels and levees, as well as the design of local sewers and storm drains. 9.5.2 Dam Failure Dams are designed partly based on assumptions about a river's hydrograph and the region's weather known at the time of construction. In the United States, the average age of a dam is almost 60 years (Fountain, 2020). In Lewis County,the average age of dams 44 years (WA Ecology, 2020). Changes in weather patterns have significant effects on hydrographs, such as early snowpack melt or heavier and more frequent rainfall, which can overwhelm dams' emergency spillways or cause structural damage. Of the ten dams on average that fail each year in the United States,the primary cause is due to excess rainfall.The most recent major dam failure on the west coast of the United States, the Oroville Dam in California in February 2017, has been attributed to warming conditions that increased snowpack melt and rainfall above the assumptions that were used to construct the dam (Huang, 2018).With these types of condition anticipated to increase in the future, more dam failure is a potential impact. 9.5.3 Wildfire Climate change can affect multiple elements of the wildfire system:fire behavior, ignitions,fire management, and vegetation fuels. Hot dry spells create the highest fire risk. Increased temperatures may intensify wildfire danger by warming and drying out vegetation. Climate change also may increase winds that spread fires and, potentially,thunderstorms producing lightning that ignites fires. Forest response to increased atmospheric carbon dioxide could contribute to more tree growth and,thus, more fuel for fires, although the effects of carbon dioxide on mature forests are still largely unknown. In turn, increased wildfires could release stores of carbon and further contribute to the buildup of greenhouse gases. 9.6 Responses to Climate Change Communities and governments worldwide are working to address, evaluate and prepare for climate changes that are likely to impact communities in coming decades. Generally, climate change discussions encompass two separate but inter-related considerations: mitigation and adaptation.The term "mitigation" can be confusing because it's meaning changes across disciplines: • Mitigation in restoration ecology and related fields generally refers to policies, programs or actions that are intended to reduce or to offset the negative impacts of human activities on natural systems. Generally, mitigation can be understood as avoiding, minimizing, rectifying, reducing, or eliminating, or compensating for known impacts (40 CFR 1508.20). 113 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • Mitigation in climate change discussions is defined as human intervention to reduce the impact on the climate system. It includes strategies to reduce greenhouse gas sources and emissions and enhance greenhouse gas sinks. • Mitigation in emergency management is typically defined as the effort to reduce loss of life and property by lessening the impact of disasters(FEMA, 2013). In this section, mitigation is used as defined by the climate change community. In the other chapters of this plan, mitigation is primarily used in an emergency management context. Adaptation is defined by the IPCC as "the process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects" (IPCC, 2014). Mitigation and adaptation are related, as the world's ability to reduce greenhouse gas emissions will affect the degree of adaptation that will be necessary.Some actions can both reduce greenhouse gas emissions and support adaptation to likely future conditions. One subset of this type of strategy is known as ecosystem-based adaptation. Ecosystem-based adaptation is the use of biodiversity and ecosystem services as part of an overall strategy to help people adapt to the adverse effects of climate change.This includes the sustainable management, conservation and restoration of specific ecosystems that provide key services. In terms of flood hazard management, many such actions are related to preserving or enhancing the natural beneficial functions of floodplain systems. Riparian forests can bind soils and hold large volumes of water during periods of significant precipitation, releasing it through the year. Floodplains can absorb large volumes of water during peak flows. Coastal ecosystems can hold out against storms, attenuating waves and reducing erosion. 114 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T PART 3 — MITIGATION STRATEGY 10.0 GOALS AND OBJECTIVES This chapter identifies the goals and objectives for reducing long-term vulnerabilities to flooding in the planning area (CRS Step 6).These vital planning components were developed by the Stakeholders through a facilitated process that addressed flooding issues, public support, political support, and existing capabilities within the planning area.They were developed to establish a vision for reducing risk to flood hazards in Lewis County.The goals and objectives are linear planning components, meaning that they all directly support one another.The Stakeholders selected objectives that met multiple goals and identified actions (identified in Table 12-1)that were prioritized based on the action meeting multiple objectives.Achievement of these goals and objectives will be pursued through an action plan that identifies the programs, projects and technical studies that will be implemented as resources are identified and allocated. 10.1 Goals The effectiveness of a mitigation strategy is assessed by determining how well its goals are achieved. The Stakeholder Committee established the following goals for the 2021 Comprehensive Flood Hazard Management Plan: Goal #1—Reduce and minimize flood related hazards to the public and emergency responders. Goal #2—Reduce and minimize flood damage and financial impacts to the community. Goal #3—Avoid impacts that cause flooding of downstream neighbors. Goal #4—Avoid, minimize, or mitigate environmental impacts of flood hazard reduction activities. Goal #5—Increase public awareness and understanding of flooding. 10.2 Objectives The Stakeholder Committee established the following objectives that meet multiple goals: 1. Utilizing the best available data and science, continually improve and annually review plans for mitigating and minimizing flood damage impacts. 2. Identify and support flood damage mitigation projects that provide the highest cost benefit and greatest protection, and avoid, minimize, or mitigate impacts on the environment. 3. Communicate flood damage risk to the public, including increased risk due to climate change, and encourage that future development recognize and minimize this risk. 4. Consider floodplain management policies that promote resiliency and sustainable operations of identified critical facilities. 5. Support the current Chehalis Basin Strategy and the Lewis County Shoreline Master Program to enhance aquatic species and restore habitat in the floodplain. 6. Promote and maintain partnerships among all levels of government, including tribal governments, and the business community to coordinate mutually beneficial mitigation strategies. 7. Continue to improve systems that provide warning and emergency communications. 8. Enhance all facets of partnership emergency response capabilities, including flood damage mitigation of vulnerable critical facilities and infrastructure. 115 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 11.0 POLICIES The Comprehensive Flood Hazard Management Plan policies,which are adopted by the Board of County Commissioners, provide the framework for making decisions about flood hazard management in the Chehalis River Basin within Lewis County.These policies also provide guidance for decision-making at the program and project level and define the level of discretion Lewis County has available in flood management decisions. When a policy uses the term "shall" or"will," it is intended that such terms be interpreted as mandatory, and that the associated action or decision is nondiscretionary.The use of "should" or"may" in a policy means that the associated action or decision is provided as guidance and indicates that there is discretion in making decisions based on such policies. The policies in this chapter are divided into four categories: • General • Flood Hazard Area Land Use • Flood Risk Reduction • Funding and Financing The policies are intended to be consistent with all water resource policies in the Lewis County Comprehensive Plan (2018) and Lewis County Shoreline Master Program (2017),which directs land use and growth.These policies do not outline policy, code or program requirements for individual jurisdictions but do call on jurisdictions to enforce policies, codes, and programs they choose to adopt. Chapter 12 of this Plan contains recommendations for flood hazard mitigation actions.These actions differ from policies in that they describe specific program and project actions that implement the Flood Plan.These actions are not mandatory.They are desirable actions that may be completed within staffing and budgetary limitations. 11.1 General Policies The general policies listed below will provide a vision for Lewis County and provide general guidance for all its activities. 11.1.1 Flood Hazard Management Watersheds do not follow jurisdictional boundaries. Actions taken by a city or county in one part of a drainage watershed,whether it be a land-use plan, development permit, or capital improvement project, can affect flood hazard problems experienced by other jurisdictions in the watershed, and can impact valuable ecological resources.Actions taken by a city or county can also have positive effects on neighboring jurisdictions. Cooperative flood hazard management between counties is supported by Chapter 86.13 RCW. Multi- jurisdictional approaches to watershed management can produce a multitude of public and private benefits, including flood risk reduction and improved ecosystem functions and values. Flood hazard management includes a range of services at both the regional and local level to reduce the risk of flood hazards.The following policies have been identified to guide the FCZD in the management of the flood hazard within the planning area. 116 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Policy G-1: Flood Hazard Management Actions The FCZD should provide flood hazard management services to reduce the risk of flood hazards, including but not limited to: a. Prepare technical studies to further identify flood hazard areas, b. Provide technical information and assistance to other agencies,jurisdictions, and individuals, c. Construct, monitor, maintain, repair, retrofit, or remove flood protection facilities, d. When feasible, preserve open space in flood hazard areas, e. Monitor conditions in the river channels and take actions, such as developing mitigation projects or supporting the County, cities, or town taking emergency actions during flood events,to reduce risks, f. Participate in flood preparedness activities g. Collaborate with other jurisdictions to implement flood risk reduction actions, and h. Take any other action deemed necessary to reduce flood related risks and the environmental impacts of flood hazard management on a regional scale. Policy G-2: Inter-Governmental Coordination and Cooperation The FCZD's flood hazard management activities should be planned and implemented in close cooperation and coordination with Lewis County,the cities and town within the Chehalis River Basin, neighboring counties, Office of the Chehalis Basin, Chehalis River Basin Flood Authority,tribes,Water Resource Inventory Area (WRIA)forums, and other agencies sharing jurisdiction in each basin.This intergovernmental coordination shall also include federal agencies, including but not limited to:the U.S. Forest Service, the U.S. Army Corps of Engineers, FEMA,the Bureau of Land Management,the National Park Service,the Bureau of Reclamation,the National Resource Conservation Service,the U.S. Fish and Wildlife Service and the National Marine Fisheries Service.This policy assumes that all federal agencies will coordinate in good faith as directed under Presidential Executive Order 11988. Policy G-3: Intra-Governmental Coordination and Cooperation In addition to the District itself,this Plan should be implemented by multiple Lewis County departments and the cities and towns that have a role in flood hazard management including, but not limited to, public works departments, community development departments, and emergency managers. Policy G-4: Multi-Objective Management Lewis County's rivers and major tributaries and their associated flood hazard areas should be managed for multiple uses and objectives. Flood hazard management actions and land uses should be encouraged that support long-term flood risk reduction outcomes. Policy G-5: Flood Hazard Management on Private Property With the exception of flood emergency response functions,flood hazard management obligations of the FCZD shall be limited to public education and awareness outreach and grant funding where the FCZD, County, or other agency may act as an eligible applicant agent for identified feasible and cost-effective flood hazard mitigation projects. District funds shall not be used for the betterment of private property outside of these parameters. 117 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RT E E T 11.1.2 Policies for Regional Consistency This Flood Plan is a comprehensive flood control management plan as defined under RCW 86.12.Though state law suggests that such plans are binding on jurisdictions within the planning area, the FCZD acknowledges that municipalities within the county have different levels of existing development,flood hazard management resources, and staff for enforcing regulations. Complete adoption by all cities of all policies in this Flood Plan may not be appropriate and is considered optional. Local flood hazard regulations and programmatic recommendations should strive for consistency, but they may be adapted to suit each city's needs and resources. The policies below are intended to provide guidance on how consistency as defined for this plan will be supported during the performance period of this plan. Policy G-6:Technical and Planning Assistance Upon request,the FCZD should assist the County, cities, or towns within the Chehalis River Basin in developing and adopting flood hazard management policies, regulations, and standards that are consistent with Policy G-2. Policy G-7: NFIP Compliance and Good Standing It should be the policy of Lewis County and all cities within the County that participate in the National Flood Insurance Program (NFIP)to maintain compliance and good standing by implementing programs that meet or exceed the minimum NFIP requirements. Such programs include but are not limited to: enforcement of an adopted flood damage prevention ordinance, limiting adverse downstream impacts from floodplain management policy, participating in floodplain mapping updates, and providing public assistance and information on floodplain requirements and impacts.The evaluation of compliance for this policy is managed by the Washington State Department of Ecology as the Washington State NFIP Coordinating Agency, and/or FEMA Region X. Policy G-8: National Flood Insurance Program When feasible, Lewis County and cities should strive to not only meet, but also exceed the federal minimum standards stipulated by the NFIP utilizing the CRS as a guide to better protect public safety, reduce the risk of flood hazards to existing public and private property, and achieve flood insurance premium discounts. 11.2 Flood Hazard Area Land Use Policies Development in flood hazard areas can create two types of challenges: • Because of its location in a hazardous area,the development may be at risk from inundation. • The development can increase risks to neighboring properties by creating a barrier to the conveyance of floodwaters,thus causing backwater flooding upstream, and by reducing the area available to store and slowly release floodwaters,thus increasing flow velocities and erosion downstream. This subsection contains policies to guide land-use planning and development regulations in flood hazard areas.The goal of these policies is to reduce flood risks to future developments and prevent increased risks to surrounding properties. 118 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T 11.2.1 Changes to Flood Hazard Areas Based on Future Conditions Historically, Lewis County flood hazard management regulations have been applied within the special flood hazard area as mapped by FEMA. FEMA maps are based on current or historical land use in the watershed. As watersheds develop, however,the rate and volume of runoff reaching rivers and streams can increase. In addition, changes in climate patterns can affect hydrologic conditions in flood hazard areas.The boundaries of the 100-year floodplain may change over time, creating inconsistencies between actual flood hazard conditions and those portrayed on FEMA maps. In addition, some rivers in Lewis County can migrate laterally, endangering properties along their banks.Areas that are at risk due to channel migration are sometimes outside mapped flood hazard areas, so that residents may not be aware of the risk. Policy FLU-1: Future Conditions The FCZD should strive to incorporate the best available data and science that utilize future condition projections for technical studies within the watersheds and basins that contribute to the flood hazards areas within Lewis County. When feasible, land use policies and flood hazard regulations should apply to flood hazard areas that utilize future conditions hydrology. Policy FLU-2: Channel Migration Zone Hazard Areas The FCZD could identify channel migration zone (CMZ) hazard areas through geomorphologic analyses, review of historical channel migration patterns and rates, and existing documentation. Any information gathered by the FZCD about CMZ hazard areas will be provided to participating municipalities to help them plan land-use regulations to restrict unsafe development in identified channel migration hazard areas. 11.3 Flood Risk Reduction Policies The policies in this section guide a comprehensive program that can implement a range of flood hazard management projects, including both structural and non-structural projects. Structural projects often involve retrofitting existing facilities, including sediment management and bank stabilization facilities. Non-structural projects could include voluntary relocation, acquisition, and elevation of flood-prone homes and the removal of existing flood hazard management structures that are no longer needed. Policy FRR-1:Selecting Flood Risk Reduction Actions Flood risk reduction actions should be selected based on consideration of the following criteria: a. Action effectively meets site-and reach-specific flood risk reduction objectives, b. Action results in a benefit that exceeds the initial cost as well as the long-term maintenance costs, c. Action does not create new unmitigated flood hazard or other problems, d. Action recognizes riparian habitat and supports adopted Water Resource Inventory Area Plan objectives where applicable, e. Action achieves public benefits, and f. Action builds upon funding and partnering opportunities. 119 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Policy FRR-2: Property Acquisition The FCZD may acquire property interests in land necessary to meet flood hazard management objectives. Except under very limited circumstances, FZCD acquisition of structures and property should be voluntary on the part of the property owner. Condemnation should be considered only under the following circumstances: a. Federal, state, or local regulations prohibit reconstruction of the building, b. The property in question is causing significant flood damage to other properties, c. A property owner refuses to sell a portion of an area in which the majority of property owners have agreed to sell to the FCZD, or d. A property owner refuses to sell an area needed to complete a proposed flood risk reduction project. Policy FRR-3: Easements Prior to participating in the construction of a new flood protection facility or maintaining, repairing, or reconstructing an existing flood protection facility, the FCZD should obtain all easements necessary to construct, maintain, repair, or retrofit the flood protection facility consistent with applicable Lewis County design and construction standards and federal and state engineering guidelines. Policy FRR-4: Management of Lewis County Properties The FCZD shall manage its public lands and easements within flood hazard areas in accordance with the policies within this Plan. Public access to flood hazard management properties will be evaluated on a case-by-case basis to determine the impact the public may have on the facility, as well as overall public safety issues. Policy FRR-5: Flood Facility Design and Maintenance Objectives The FCZD should construct new flood protection facilities and maintain, repair, or replace existing flood protection facilities in such a way as to: a. Require minimal maintenance over the long term, b. Ensure that flood hazard problems are not transferred to other sites, c. Maintain or enhance aquatic, riparian, and other critical area habitat where feasible, and d. Minimize impacts on flood hazard areas within areas that provide fish and wildlife habitat, recreational opportunities, and productive agricultural soils. Policy FRR-6: Monitoring and Adaptive Management Flood hazard management projects shall be monitored to assess their function relative to established performance measures.Adaptive management shall be used to modify the project to improve the effectiveness of the project and to inform the design and implementation of future projects. 11.4 Funding and Financing Policies The recently formed FCZD requires the establishment of policies to govern when it will spend money on capital projects, maintenance of facilities, repairs, and emergency work throughout the county and the incorporated cities. The District has limited funds and cannot meet all the drainage or flood hazard reduction needs of all the communities within the county and is designed primarily to deal with public infrastructure and safety, not small local drainage issues.The policies in this section provide a 120 NOVEMBER 2021 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T framework for making decisions about how these funding sources are used for flood hazard management in Lewis County. Policy FF-1: Management of the District The District Administrator will exercise best professional judgment in conjunction with the direction of the Board of Supervisors to determine the appropriate courses of action for all circumstances or events within the province of the FCZD,whether or not such events or circumstances are anticipated and addressed in this document. Policy FF-2: Regional Funding New or expanded regional funding sources should be identified to meet the need for enhanced or expanded flood hazard management projects and programs to address flood impacts. Policy FF-3:Grant Funding The participating municipalities with the boundaries of the Chehalis River Basin FCZD and other local government agencies should identify,evaluate, and coordinate grant funding sources to determine their suitability and assess consistency with the goals and objectives of this Plan, and apply for grants to leverage local sources of funding for flood risk reduction projects. 121 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 12.0 MITIGATION ACTIONS 12.1 Alternatives Analysis 12.1.1 Mitigation Alternative Catalog Prior to selecting mitigation actions,the stakeholder committee identified a comprehensive range of alternatives that Lewis County could consider to mitigate the flood issues identified by the Flood Plan. The alternatives provided a wide range of activities to ensure that all possible measures are explored, beyond the traditional approaches of flood control, acquisition, and regulation of land use. Presenting a complete range of possible alternatives diversifies the Comprehensive Flood Hazard Management Plan and positions it to be able to respond to changing conditions affecting the flood hazard.An action that might not be feasible today could become feasible in the future due to a change in programs, capabilities,or available resources.The items in this section provide options for the County to consider as it implements and maintains this Plan,to address changing conditions in mapped flood hazard areas. The Stakeholders held a meeting on June 23, 2020,to assess local strengths,weaknesses, obstacles, and opportunities related to flood hazard management.This meeting was the basis for considering and selecting mitigation actions for the flood hazard management plan.The planning team prepared a catalog of mitigation alternatives based on the findings of this meeting. The catalog was categorized in two ways: • Responsibility for implementation: o Public sector(citizens of Lewis County) o Private sector(non-governmental parties) o Government sector(federal, state, and local) • Flood mitigation alternatives that: o Manipulate the flooding hazard. o Reduce exposure to the flooding hazard. o Reduce vulnerability to the flooding hazard. o Increase the ability to respond to or be prepared for the flooding hazard. The catalog provided the stakeholders a baseline list of mitigation alternatives that are backed by a planning process, are consistent with the goals and objectives, and are within the capabilities of Lewis County to implement.The mitigations alternatives catalog is provided in Appendix D. 12.1.2 Past Action Review In addition to the mitigation alternatives catalog,the planning team also gathered actions from different plans, proposals, and programs, such as the Lewis County Multi-jurisdictional Hazard Mitigation Plan, the Chehalis Basin Strategy, and the Chehalis River Basin Flood Authority. These actions spanned a wide range of time as a result of the planning efforts implemented after the 2007 flood. During their initial review,the planning team removed actions that have been completed or are outdated due to changes in conditions, procedures, or regulations. During their second review,the planning team combined and updated actions with a goal of clarifying and simplifying the list and making actions relevant to today's needs and regulatory conditions.The updated action list was presented to the Stakeholder Committee, 122 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T who directed the planning team to set up a separate Action Development Meeting for more in depth discussion. 12.1.3 Action Selection During the Action Planning Meeting,the planning team and agency staff discussed the mitigation action catalog and the updated list of past actions. Not all possible actions met all the selection criteria considered by the stakeholders, and several required additional edits and clarification. All actions were throughout reviewed and discussed.The selected actions are discussed in the next section. The selected actions include a mix of programmatic actions that will support regulation, public education, and response efforts, and are alternatives to instream flood control work.The selected actions do not include any specific instream flood control projects but do identify several actions which may lead to instream flood control, such as bank stabilization, bridge replacement,flood retention, or new levees. These provides direction to the FCZD and other Lewis County agencies to conduct studies and analysis and continue participating in project development processes. It gives them opportunity to choose which projects to support for implementation based on the merits and impacts of each project as they are proposed and reviewed.This plan provides the planning partners a set of goal, policies, and objectives they can use to evaluate which projects they intend to support and implement. 12.2 Mitigation Action Plan Table 12-1 lists the actions selected during the Action Development Meeting and the following information: • Whether the action applies to new or existing assets. • The types of flood hazards mitigated: o All flooding o Riverine flooding and erosion o FEMA floodplains • The objectives met(Section 10.2) • The lead agency responsible for implementing the action. Mitigation actions may be implemented by one or more of the agencies that participated in this planning effort. Not all mitigation actions apply to all agencies. • The estimated cost: o High—Existing funding will not cover the cost of the project; implementation would require new revenue through an alternative source (for example, bonds, grants, and fee increases). o Medium—The project could be implemented with existing funding but would require a re- apportionment of the budget or a budget amendment, or the cost of the project would have to be spread over multiple years. o Low—The project could be funded under the existing budget.The project is part of or can be part of an ongoing, existing program. • Potential sources of funding to implement the action. • Timeline for implementation: o Short-term—Action to be completed in 1 to 5 years. 123 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN PE RTE E T o Long-term—Action to be completed in greater than 5 years. o Ongoing—Action currently being funded and implemented under existing programs. Table 12-1. Flood Mitigation Action Plan Matrix. Applies to New Flood Hazards Objectives Estimated Sources of or Existing Timeline Mitigated Met Lead Agency Cost Funding Assets Action#1—Continue participation and implementation of the flood damage reduction projects that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis Basin. (See Section 12.6 for more details on this action) New and OCB, Flood Short-term, All flood hazards All FCZD High Authority FCZD, existing Ongoing grants Action#2—Develop a technical assistance program to support landowners with bank stabilization and/or post- disaster debris removal. New and Riverine flooding County, possible existing and erosion 2 FCZD Medium grant funding Short-term Action#3—Develop a Newaukum Unit Drainage Basin Plan for Dillenbaugh, Dilly,and Berwick Creeks. Develop a comprehensive drainage basin plan to identify cost effective and feasible structural and non-structural actions that will minimize future peak flow increases.The study should include the area between Armstrong Road and Jackson Highway adjacent to Logan Hill Road. FCZD, FCD,City of New and Chehalis, Port of County,Cities, Short-or existing All flooding 1,2,6,8 Chehalis,and Lewis High Districts, possible long-term County Public grant funding Works Action#4—Identify sources of local funding for the FCZD to fund FCZD administration and leverage alternative funding sources. New and All flooding 1,2,3,5 FCZD Low County Short-term existing Action#5—Identify alternative sources of funding to leverage FCZD funding to perform new flood studies in identified areas of need based on risk. OCB,Flood New All flooding 1,2,6 FCZD Low Authority, Short-term possible grants Action#6—As FCZD projects are constructed,monitor projects using identified performance measures and adaptive management to track the effectiveness of completed projects to inform the design and implementation of future projects. New All flooding 1,2 FCZD Low County Long-term Action#7—When requested, FCZD may act as the applicant agent for mitigation grant opportunities for private property requesting to participate in the grant program. Existing All flooding 1,2,3 FCZD Medium County Ongoing Action#8—Maximize federal,state,and local funding opportunities through grant application submittals in support of capital improvement projects,technical studies,and other flood hazard management activities. Existing All flooding 1,2, 6 FCZD Medium County,Cities Ongoing Action#9—Mitigate flood related risk to publicly owned County and City bridges. County,Cities, Long-term, Existing All flooding 1,2,4, 6,8 Public Works High possible grant funding Ongoing 124 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Applies to New Flood Hazards Objectives Estimated Sources of or Existing Timeline Mitigated Met Lead Agency Cost Funding Assets Action#10—Maintain database of flood control needs within the planning area as needs become identified for incorporation into future updates and progress reporting to this plan. FCZD, Public Works, 1, 2,4,5,6, Planning, Existing All flooding 7 8 Emer enc Low County,Cities Ongoing g y Management Action#11—Inform future mapping,grant applications,studies,and other activities by maintaining a database on known flood risk that tracks historical flood conditions to include,but not be limited to: high water marks,recorded damages,photos,observed flood conditions,etc. FCZD, Public Works, New and All flooding 1,3,7 Planning, Low County,Cities Ongoing existing Emergency Management Action#12—Utilizing the best available data,science, and technology, maintain and enhance,as data becomes available,the Level 2, user-defined Hazus-MH model that was constructed to support this planning effort. New and All flooding 1,2,3,8 GIS Medium County Ongoing existing Action#13—Offer the Chehalis River Basin Comprehensive Flood Hazard Management Plan as information available for integration into other appropriate plans and programs that can support or enhance the participating jurisdictions efforts to reduce flood risk as these plans and programs are updated. Examples of such plans/programs would include but are not limited to: Lewis County Hazard Mitigation Plan, Lewis County Comprehensive Plan,and Lewis County Shoreline Master Program. New and All flooding 1,3 FCZD, Public Works, Low County ongoing existing Planning,Cities Action#14—Lewis County and the Cities of Centralia and Chehalis will continue participating in the Community Rating System(CRS)process. Existing All flooding 1,2,3,4,5, Planning,Cities Low County,Cities Ongoing 6,7,8 Action#15—Deploy public information and outreach program targeting at-risk properties within the planning area. Existing All flooding 3 FCZD, Emergency Low County,Cities Ongoing Management,Cities Action#16—Coordinate with FEMA Region X on deploying flood insurance workshops for agents, lenders,and citizens within the performance period for this plan. FCZD, Planning, Existing All flooding 6 Emergency Low FEMA Ongoing Management Action#17—Participate and coordinate with the Office of the Chehalis Basin,the Chehalis River Basin Flood Authority, and other pertinent Chehalis Basin organizations to ensure projects and programs are consistent with larger basin- wide objectives. New and All flooding 1,2,4,5,6, FCZD Low County,Cities Ongoing existing 7,8 Action#18—Participate in updates to the County's Flood Insurance Rate Maps to ensure the maps accurately reflect local conditions. New and All FEMA Planning, Public County,Cities, Existing floodplains 1,3 Works,Cities, FCZD, Medium FEMA Short-term Cities Action#19—Include CMZs,dam and levee breach inundation areas,and other critical areas as informational layers in the County's online public web map. 125 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Applies to New Flood Hazards Objectives Estimated Sources of or Existing Timeline Mitigated Met Lead Agency Cost Funding Assets New and All flooding 1,3,4,6,7, GIS, Planning Low County Ongoing Existing 8 Action#20—Encourage FEMA and NFIP training for County and City staff that administer floodplain regulations and FEMA grant programs. Emergency New and All FEMA Management, Existing floodplains 3 Planning, FCZD, Medium County,Cities Ongoing Cities Action#21—Provide outreach and educational materials for the public on flood hazards, risks of development in floodplains, NFIP regulations,and flood mitigation programs,including annual mailings to flood prone properties and placing flood information at local libraries. New and All FEMA Existing floodplains 3 Planning,Cities Low County,Cities Ongoing Action#22—Maintain the flood information website on the FCZD web page to provide Chehalis River Basin information and links to the flood warning system and all other related websites and information. New and Existing 3,7 FCZD Low County Ongoing Action#23—Maintain an inventory of properties located in the floodplain. New and All FEMA Existing floodplains 1,2,6 Planning,Cities Low County,Cities Ongoing Action#24—Continue to support projects that evaluate the feasibility of regional stormwater detention facilities to address increased stormwater runoff for development in the basins that occurred prior to implementation of site- specific stormwater management measures. Surface water County, Existing flooding 1,2, 6 FCZD, Public Works Medium possible grant Ongoing funding Action#25—Maintain a database of properties that experience repetitive flooding,to include properties identified as Repetitive Loss(RL)properties.The County will establish a procedure for updating the list annually or following a flood event,as necessary.The database will be used to establish a prioritized list of properties that would benefit from mitigation or acquisition,and to provide the owners of the properties information about available funding. Existing All FEMA 1,2 Planning,Cities Low County,Cities Ongoing floodplains Action#26—Participate in developing flood control projects with other entities such as the Chehalis River Basin Flood Authority,Office of the Chehalis Basin, USACE,and the Washington State Department of Transportation(WSDOT). New and All flooding 2,4,6,8 FCZD, Public Works, Medium County,OCB, Ongoing Existing Cities Flood Authority Action#27—Perform a field examination of all flood control structures and create a database of the information, including ownership and maintenance responsibilities. Determine the maintenance responsibility of each structure. County, Existing All flooding 1,6 FCZD, Public Works Medium Long or possible g rant short-term funding Action#28—Support projects that would mitigate or relocate utilities and critical facilities which are subject to flooding. Existing All flooding 2,4,6,8 Medium- Grants, FEMA Long-term High Action#29—Encourage NIMS/ICS training for County and City staff that may work within or interact with the Emergency Operations Center(EOC). New and All flooding 7 Emergency Low County Ongoing Existing Management 126 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Applies to New Flood Hazards Objectives Estimated Sources of or Existing Timeline Mitigated Met Lead Agency Cost Funding Assets Action#30—Develop a flood response plans,such as debris management plans,to include response and recovery roles, responsibilities, and priorities,flood early warning system procedures, pre-identified detour routes,criteria to assist emergency response personnel in determining what actions are appropriate when providing assistance to private property during the response and recovery phases,and a list of not-for-profit essential service providers that provide community support during and after a flood event. Emergency New and Public All flooding 1,8 Management, Medium County, FEMA Short-term Existing Works, FCZD, Planning Action#31—Develop and/or review adequacy of mutual aid agreements and procure on-call service contracts to assist with demand for human resources following a disaster. New and FCZD, Public Works, Existing All flooding 8 Emergency Low County,Cities Short-term Management,Cities Action#32—Maintain a database of all known past problem areas.This database should be linked to GIS for easy visual examination.The County should update the database after each flood event to ensure that the information is captured for future mitigation grant opportunities. County Planning, County, road Existing All flooding 1,2 Public Works,GIS, Low fund Short-term Cities Action#33—Assign a staff member to become familiar with the FEMA Stafford Act Section 406 mitigation assistance program and identify potential new mitigation funding opportunities. New and FCZD, Emergency All flooding 8 Management, Public Medium County Short-term Existing Works Action#34—Coordinate with WA EMD to ensure County staff attends annual preliminary damage assessment training. New and FCZD, Emergency Emergency Existing All flooding 8 Management, Public Low Management Short-term Works Action#35—Prevent adverse impacts to the floodplain by requiring all new commercial,industrial, multi-family,and subdivisions to demonstrate no adverse impact. New and All FEMA 1,2 County Planning, Medium County,Cities Short-term Existing floodplainsCities Action#36—Continue to maintain good standing under the National Flood Insurance Program by implementing programs that meet or exceed the minimum NFIP requirements.Such programs include enforcing an adopted flood damage prevention ordinance, participating in floodplain mapping updates,and providing public assistance and information on flood hazard requirements and impacts. New and All FEMA County Planning, Existing floodplains 1, 2,3 Cities Low County,Cities Short-term Action#37—Develop a communication protocol plan and provide training to all County and city responders on new protocol and system upgrades as funding becomes available. New and All flooding 7 8 Emergency Medium Emergency Short-term Existing Management Management Action#38—Map detour routes and share routes with WSDOT to assist in efficient detour planning. New and Emergency Existing All flooding 8 Management, Public Medium Road fund Short-term Works Action#39—Support updates to the flood warning system to ensure it utilizes the best available data,science,and technology. 127 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Applies to New Flood Hazards Objectives Estimated Sources of or Existing Timeline Mitigated Met Lead Agency Cost Funding Assets New and FCZD,Emergency OCB, Flood All flooding 3, Existing Management Authority Action#40—Utilize the best available data,science,and technology in District led projects, programs,and outreach. New and FCZD, Emergency All flooding 1, 2, 6High County Short-term Existing Management 12.3 Benefit/Cost Review The action plan is prioritized according to a benefit/cost analysis of the proposed projects and their associated costs (CRS Step 8).The benefits of proposed projects were weighed against estimated costs as part of the project prioritization process.The benefit/cost analysis was not of the detailed variety required by FEMA for project grant eligibility under the Hazard Mitigation Grant Program (HMGP) and BRIC grant program.A less formal approach was used because some projects may not be implemented for up to 10 years, and associated costs and benefits could change dramatically in that time.Therefore, a review of the apparent benefits versus the apparent cost of each project was performed. Parameters were established for assigning subjective ratings (high, medium, and low)to the costs and benefits of these projects. Benefit ratings were defined as follows: • High—Project will provide an immediate reduction of risk exposure for life and property. • Medium—Project will have a long-term impact on the reduction of risk exposure for life and property, or project will provide an immediate reduction in the risk exposure for property. • Low—Long-term benefits of the project are difficult to quantify in the short term. Cost ratings were defined as follows: • High—Existing funding will not cover the cost of the project; implementation would require new revenue through an alternative source (for example, bonds,grants,and fee increases). • Medium—The project could be implemented with existing funding but would require a re- apportionment of the budget or a budget amendment, or the cost of the project would have to be spread over multiple years. • Low—The project could be funded under the existing budget.The project is part of or can be part of an ongoing, existing program. Using this approach, projects with positive benefit versus cost ratios (such as high over high, high over medium, medium over low, etc.) are considered cost-beneficial and are prioritized accordingly. For many of the strategies identified in this action plan, Lewis County agencies may seek financial assistance under the FEMA HMGP or Hazard Mitigation Assistance programs, both of which require detailed benefit/cost analyses.These analyses will be performed on projects at the time of application using the FEMA benefit-cost model. For projects not seeking financial assistance from grant programs that require detailed analysis, Lewis County reserves the right to define "benefits" according to parameters that meet the goals and objectives of this Plan. 128 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 12.4 Action Plan Prioritization Table 12-2 lists the priority of each action as assigned by the Planning Team, using the same parameters used in selecting the actions. A qualitative benefit-cost review was performed for each of these actions.The priorities are defined as follows: • High Priority—A project that meets multiple objectives, has benefits that exceed cost, has funding secured or is an ongoing project and meets eligibility requirements for a grant program. High priority projects can be completed in the short term (one to five years).The key factors for high priority projects are that they have funding secured and can be completed in the short term. • Medium Priority—A project that meets goals and objectives,that has benefits that exceed costs, and for which funding has not been secured but that is grant eligible. Project can be completed in the short term once funding is secured. Medium priority projects will become high priority projects once funding is secured.The key factors for medium priority projects are that they are eligible for funding, but do not yet have funding secured, and they can be completed within the short-term. • Low Priority—A project that will mitigate the risk of a hazard,that has benefits that do not exceed the costs or are difficult to quantify,for which funding has not been secured, that is not eligible for FEMA grant funding, and for which the timeline for completion is long term (one to 10 years). Low priority projects may be eligible for grant funding from other programs. Low priority projects are "blue-sky" projects. How they will be financed is unknown, and they can be completed over the long-term. Table 12-2. Prioritization of Mitigation Actions. Number Do benefits Is Can project be of equal or project funded using Action Benefits Costs existing Priority(high, objectives exceed grant met costs? eligible? programs/ med.,low) budgets? #1 All Medium High Yes No Yes High #2 4 Medium Low Yes Yes No High #3 4 Medium High Yes Yes No Medium #4 4 High Low Yes No Yes High #5 3 High Low Yes Yes No Low #6 2 Medium Low Yes No Yes Medium #7 3 High Low Yes No Yes Medium #8 3 High Medium No Yes No Low #9 5 High High No Yes No Low #10 7 High Low Yes No Yes High #11 3 High Low Yes No Yes High #12 4 High Low Yes No Yes High #13 2 High Low Yes No Yes High #14 8 High Low Yes No Yes High #15 1 High Low Yes Yes Yes High 129 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T #16 1 High Low Yes No Yes High #17 7 High Low Yes No Yes High #18 2 High Medium Yes No No Medium #19 6 High Low Yes No No Medium #20 1 Medium Medium Yes No Yes High #21 1 High Low Yes No Yes High #22 2 High Low Yes Yes Yes High #23 3 Medium Low Yes No Yes High #24 3 Medium Medium No Yes Yes High #25 2 High Low Yes No Yes High #26 4 High Medium N/A Yes No Low #27 2 High Medium Yes No No Medium #28 4 High High N/A Yes No Low #29 7 High Low Yes No Yes High #30 2 High Medium Yes Yes No Medium #31 1 Medium Low Yes No No Medium #32 2 Medium Low Yes No Yes High #33 1 High Low Yes No Yes Medium #34 1 High Low Yes No No Medium #35 2 High Medium Yes No Yes High #36 3 High Low Yes No No Medium #37 2 High Medium Yes No Yes Medium #38 8 High Medium Yes No Yes High #39 2 High High Yes Yes No High #40 3 High High Yes Yes No Low 12.5 Analysis of Mitigation Actions Each identified action was classified based on the type of mitigation it involves. Mitigation types used for this categorization are as follows: • Prevention—Government, administrative or regulatory actions that influence the way land and buildings are developed to reduce hazard losses. Includes planning and zoning,flood hazard management laws, capital improvement programs, open space preservation, and stormwater management regulations. • Property Protection—Modification of public buildings, roads, or structures to protect them from a hazard or removal of structures from a hazard area. Includes acquisition, elevation, relocation, structural retrofit, storm shutters,and shatter-resistant glass. • Public Education and Awareness—Actions to inform citizens and elected officials about flood hazards and ways to mitigate them. Includes outreach projects, real estate disclosure, hazard information centers, and school-age and adult education. • Natural Resource Protection—Actions that minimize hazard loss and preserve or restore the functions of natural systems. Includes sediment and erosion control,stream corridor restoration,watershed management,forest and vegetation management, and wetland restoration and preservation. 130 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • Emergency Services-Actions that protect people and property during and immediately after a hazard event. Includes warning systems, emergency response services, and the protection of essential facilities. • Structural Projects-Actions that involve the construction of structures to reduce the impact of a hazard. Includes dams,setback levees,floodwalls, retaining walls, and safe rooms. Table 12-3 presents the results of this analysis. Table 12-3. Mitigation Actions Analysis. Mitigation Type Applicable Mitigation Actions 1. Prevention 1, 3,4, 5, 8, 9, 10, 11, 12, 14, 17, 18, 19, 20, 23, 24, 25, 27, 28, 30, 31, 32, 33, 36, 39, 40 2. Property Protection 1, 2,4, 7, 35,40 3. Public Education and Awareness 1, 4, 13, 15, 16, 19, 21, 22, 39, 40 4. Natural Resource Protection 1, 2,4, 35,40 5. Emergency Services 1,4, 22, 28, 29, 30, 31, 32, 34, 37, 38, 39 6. Structural Projects 1, 3,4, 6, 24, 26, 27, 40 12.6 Action #1 - Chehalis Basin Strategy The goal of the Chehalis Basin Strategy is to reduce flood damage and improve aquatic habitat throughout the Chehalis Basin,from the headwaters above Pe ElI,to the mouth of the Chehalis River in Gray's Harbor. For more background on the history of the Chehalis Basin Strategy, see Section 4.1. Over the years,the Chehalis Basin Strategy has funded and supported a variety of projects within Lewis County, including protecting the wastewater treatment plant in Pe ElI, removing fish barriers, reconnecting stream channels, and conducting studies and analysis to support implementation of future projects.The Chehalis Basin Strategy will continue funding and supporting projects into the future, including projects that are not currently proposed or known. These projects are included under Action #1-Continue participation and implementation of the flood damage reduction projects that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis Basin. Two of the major instream flood damage reduction projects proposed through the Chehalis Basin Strategy are the flood retention facility near Pe ElI and improvements to the Chehalis-Centralia Airport Levee.These projects went through a Programmatic Environmental Impact Statement process which evaluated a wide range of alternatives in 2017.At the time of this plan's adoption,the projects are under draft SEPA and NEPA EIS review with the FCZD as the project owner and applicant. Potential impacts of the flood retention facility and the airport levee have been thoroughly researched, documented, and evaluated in a variety of studies, reports, and environmental review documents prepared over the past several years.These documents can all be accessed through the FCZD website. 12.6.1 Flood Retention Facility The FCZD proposes to construct a flood retention facility and associated temporary reservoir near Pe ElI to reduce damages during a major flood. It will not protect communities from all flooding, nor is it designed to stop regular annual flooding from the Chehalis River.The facility would only store 131 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T floodwater during major floods and then slowly release retained floodwater when it is safe to do so and over a period of time.A major flood is defined as 38,800 CFS, or a flood with a 15% probability of occurring in most years (7-year recurrence interval). Most of the time,the Chehalis River would flow through the structure's low-level outlet works at its normal rate of flow and volume—and allow fish to pass both upstream and downstream. During a flood event similar to 2007 and 1996, a 6.2 mile long reservoir would form behind the facility holding 65,000 acre feet of flood water.The facility would be 1,220 feet wide and 254 feet tall. Figure 12-2 illustrates the proposed facility. Figure 12-1. Flood Retention Facility Project. Flood Retention Facility tr'-' .•--, ." .- Overflow Spillway ,s. Normal Flow and •d - Fish Passage Tunnels Fish Passage Facility F Spillway .1 # . Flip Bucket Als .= '' '-ti.:. - V. / .'* _ ,�,[,y��iC '�J .'r�l ♦� s s dIF Low Level Outlet ., '.• ••• sc. , 4 .y�.•-w ,"f� Works Stilling Basin *! I t y A a`w , ... if 4 dr.- ,j ,}., ..,, I. qr ,r1 Construction �..� «.:• T` � •44'1 . DiversionOutlet -r - * :i` A `; i- ', Chehalis River " ` ..-1. Y' r� -Z'3- •...4 � �r '^� � i ma' '`� � j�l r Source:OCB Figure 12-2 illustrates the reduction in flooding during a 100-year flood in the Pe Ell area as a result of the flood retention facility.The red areas show the modeled 100-year floodplain if there is no action taken.The blue areas are the modeled 100-year floodplain after the facility is constructed, demonstrating a significant reduction in flooding. 132 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 12-2. Flooding reduction as a result of Flood Retention Facility. ,.,.IIVw 1i �� +�u fire r r n ti preba!!s Rhrer r i J J/)Y r i v"t 1500,.. .. - , . . _ .....„. .., . rp, ....., . -.':"; f. °I..". LF"'edlitli �. .,r►...�r �„+i�� ,�' South Fork 7 " -may t ~ j" l r "di ` ' :=r �w/� r Chehalis River ��- :4:4V,.. _= jam l,i -,,,, k Pe EII *+ ._ � fr.-V. ' - sr o a� .Ak�� id • 7 f tbr' ,,4.0. �Proposed Flood i LL ,,,� „ Retention Facility '......y�+ , Legend ,. Q Upper Chehalis Watershed �- Y .. 1 LewisQ County Boundary • '• �♦"„ Y —Planning Area Watercourses T7 r/ Planning Area 0. 1 O Citics A `'.. ,,� 17 r �;J�,f < -- Modeled 100-Year Floodplain with Action iiiiil• �r ' • ♦ �,, Modeled 100-Year Floodplain with No Action if 1 -t 1 r .t r i to Source Offce of the Chehalis Boson,FEMA,Lewis County,ESRI M,le, ,�'� A /r' .'/ r+ 12.6.2 Airport Levee The FCZD proposes to construct levee improvements at the Chehalis-Centralia Airport.The levee improvements will protect the airport, local businesses, and area transportation from a 100-year flood. The existing levee height will be raised four-to seven-feet and a portion of Airport Road would be raised to meet the same height of the improved levee. Figure 12-3 shows the location of the levee improvements. 133 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Figure 12-3.Airport Levee Project. xe ,..laill -. - , ....';--t.; „:44: ]..'1,7_' - - - ,,‘ ..,.. :- - -- ,, -:" -, - : jy"..;,. . 4, 4*-t1-1::,.ii„11'f::', ',* ,- 'k f 0 . _ — ' II hehalis i — ..,.,, :, ... . { •_ fil N' 11" ._.. a �5 ArA; • 4 - rt "Aiil .�'S4r .. � r: T y+ t e �► a .-..'•. _lt 4 • Ilti 'A"' Airport Levee Improvements , .['`'. t.' Airport Levee Improvements x it Raised Road ►V Existing Feet 'w,►„ Z 0 1,000 2,000 .„.." Railroad .. , in. MI L' 9Wrr Source:OCB Figure 12-4 illustrates the reduction in flooding during a 100-year flood in the Centralia and Chehalis area because of the flood retention facility and airport levee.The red areas show the modeled 100-year floodplain if there is no action taken.The blue areas are the modeled 100-year floodplain after the facility is constructed and the levee is improved, demonstrating a significant reduction in flooding. 134 NOVEMBER 2021 1 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Figure 12-4. Flooding reduction as a result of Flood Retention Facility and Airport Levee. "a r~ Ae am _.. ,� � - _�. , ',if 4 / ..t "Ifoia, �0,;It , 'rie o N " =.� Centralia `„ost r s 4, C'hchnlis River ,4- y it Chehalis-Centralia k+.r ,x ,/ ;, Airport Levee Chehalis +y rr r „, .r fi r j`+ , s 1 r ,• PERTEET i Legend r��'' J Upper Chehalis Watershed it Q Lewis County Boundary —Planning Area Watercourses =Planning Area •ft ,,• . 0 Cities rid Modeled 100-Year Floodplain with Action South Fork M.Modeled 100-Year Floodplain with No Action Chehalis River r 0 2 4 Date.8/22/2021 1 i I I I Source.Offceo the Chehalis Basin.FEMA.Lesvos County;ESRI ,. Miles I 12.6.3 Economic Benefit of Flood Reduction Projects The planning team was provided depth grids for the flood models that included the flood reduction projects and used the models to run Hazus analyses.The results of the Hazus analyses indicate a major reduction in damage after the projects are constructed.Table 12-4 describes the economic impacts as determined by the Hazus analyses. These estimates do not include damage to infrastructure like road, water, or sewer systems, or economic impact due to business or Interstate 5 closures. The results indicate that during the modeled 100-year flood event, which is similar to both the 1996 and 2007 floods,the projects will reduce damages to structures and content by about$241 million,or 71 percent. In addition, after the project is constructed there will be about 6,600 less tons of debris to clean up and about 1,700 fewer people displaced. 135 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T During the 100-year climate change flood event,the project will reduce damage to structures and content by about$330 million, or almost 50 percent. In addition, after the project is constructed there will be 11,100 less tons of debris to clean up and about 1,800 fewer people displaced. Damage reductions during the 10-year event are still significant with a 24 percent reduction in damages to structures and content, but lower than the 100-year event. This is due to the design of the facility, which will begin retaining flood waters during the 7-year flow, so a much smaller percentage of floodwaters will be retained in the 10-year even compared to a larger flood event. Table 12-4. Economic Impacts of Flood Reduction Project. 100-Year Modeled Flood Without Flood Reduction Project With Flood Reduction Project . . Structures Content Value Structures Content Value Centralia 1,573 $110,362,968 998 $42,271,698 Chehalis 300 $158,251,600 151 $23,425,813 Napavine 1 $53,096 1 $53,096 Pe ElI 7 $298,661 2 $37,283 Unincorporated County 629 $67,344,440 375 $29,510,092 Total 2,510 $336,310,766 1,527 $95,297,983 100-Year Climate Change Flood Without Flood Reduction Project With Flood Reduction Project Structure and ontent Value Structures Content Value Centralia 2,501 $293,747,580 1,987 $128,905,547 Chehalis 390 $253,094,012 303 $140,450,699 Napavine 5 $831,338 5 $831,338 Pe ElI 9 $554,042 2 $66,612 Unincorporated County 985 $120,728,936 637 $68,568,219 Total 3,900 $668,955,909 2,934 $338,822,416 10-Year Modeled Flood Without Flood Reduction Project With Flood Reduction Project Impacted Structure and Impacte' Structure and Structures Content Value Structur= Content Value Centralia 225 $9,840,106 220 $9,162,842 Chehalis 61 $8,073,920 28 $5,562,993 Napavine 0 $0 0 $0 Pe ElI 2 $44,114 2 $20,969 Unincorporated County 189 $15,132,033 141 $10,634,086 Total 477 $33,090,174 391 $25,380,890 1 Impacted structures are those with finished floor elevations below the Hazus-estimated 100-year or 10-year water surface elevation for each flood event.These structures are the most likely to receive damage in a flood event. Notes:Values in this table are only for purposes of comparison among results.See Section 5 for a discussion of data limitations. Sources of data used in Hazus modeling are described in Section 5. 136 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T PART 4 - PLAN MAINTENANCE 13.0 ADOPTION This chapter documents formal adoption of the Chehalis River Basin Comprehensive Flood Hazard Management Plan by the Chehalis River Basin Flood Control Zone District Board of Supervisors and Lewis County's governing body(CRS Step 9).A copy of the resolutions is provided on the following pages. Figure 13.1. FCZD Adoption Resolution. Figure 13.2. Lewis County Commissioners Adoption Resolution. Figure 13.3. Chehalis City Council Adoption Resolution. 137 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 14.0 PLAN MAINTENANCE STRATEGY This chapter presents a plan maintenance process that includes the following (CRS Step 10): • A section describing the method and schedule of monitoring, evaluating, and updating the flood hazard management plan over a five-year cycle. • A process by which local governments incorporate the requirements of the mitigation plan into other planning mechanisms, such as comprehensive or capital improvement plans, when appropriate. • A discussion on how the community will continue public participation in the Flood Plan maintenance process. The plan maintenance strategy is the formal process that will ensure that the Comprehensive Flood Hazard Management Plan remains an active and relevant document. It includes a schedule for monitoring and evaluating the Flood Plan annually and producing an updated plan every five years.The strategy also describes how public participation will be integrated throughout the plan maintenance and implementation process. It explains how the mitigation strategy outlined in this plan will be incorporated into existing planning mechanisms and programs, such as comprehensive land-use planning processes, capital improvement planning, and building code enforcement and implementation. The Flood Plan's format allows sections to be reviewed and updated when new data become available, resulting in a plan that will remain current and relevant. 14.1 Plan Implementation The effectiveness of the Comprehensive Flood Hazard Management Plan depends on its implementation and incorporation of its action items into existing local plans, policies, and programs.Together,the action items in the Flood Plan provide a framework for activities that Lewis County can implement over the next five years.The planning team and the Stakeholder Committee have established goals and objectives and have prioritized mitigation actions that will be implemented through existing plans, policies, and programs. Lewis County's Chehalis River Basin Flood Control Zone District in cooperation with the County and other communities will have lead responsibility for overseeing the Flood Plan implementation and maintenance strategy. Plan implementation and evaluation will be a shared responsibility among all agencies identified as lead agencies in the mitigation action plan. 14.2 Stakeholder Committee The Stakeholder Committee oversaw the development of the Flood Plan and made recommendations on key elements of the plan, including the maintenance strategy. It was the Stakeholder Committee's position that an oversight committee should have an active role in the plan maintenance strategy. Therefore, it is recommended that the Stakeholder Committee remain a viable body involved in key elements of the plan maintenance strategy. The principal role of the Stakeholder Committee in this plan maintenance strategy will be to meet annually to review the annual progress report and to provide input to Lewis County's Flood Control Zone District on possible enhancements to be considered at the next update. Future updates will have 138 NOVEMBER 2021 1 COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T participation by a Stakeholder Committee similar to the one that participated in this plan development process, so keeping the stakeholder committee intact will provide a head start on future updates. It will be the Stakeholder Committee's role to review the progress report to identify issues needing to be addressed by future plan updates. 14.3 Annual Progress Report The minimum task of the ongoing annual Stakeholder Committee meeting will be the evaluation of the progress of its individual action plan during a 12-month performance period.This review will include the following: • Summary of any flood hazard events that occurred during the performance period and the impact these events had on the planning area. • Review of mitigation success stories. • Review of continuing public involvement. • Brief discussion about why targeted strategies were not completed. • Re-evaluation of the action plan to determine if the timeline for identified projects needs to be amended (such as changing a long-term project to a short-term one because of new funding). • Recommendations for new projects. • Changes in or potential for new funding options (grant opportunities). • Impact of any other planning programs that involve hazard mitigation. The planning team has created a template for preparing a progress report(see Appendix C).The Stakeholder Committee and identified lead agencies will provide feedback to the planning team on items included in the template.The planning team will then prepare a formal annual report on the progress of the plan.This report should be used as follows: • Posted on the Flood Control Zone District program website page dedicated to the Comprehensive Flood Hazard Management Plan. • Provided to the local media through a press release. • Annual flood meeting. • Presented to the Lewis County Commissioners and City Council to inform them of the progress of mitigation actions implemented during the reporting period. • Provided as part of the CRS annual re-certification package.The CRS requires an annual recertification to be submitted by October 15 of every calendar year for which the community has not received a formal audit.To meet this recertification timeline,the planning team will strive to complete progress reports between June and September each year. Annual progress reporting is credited under CRS Step 10. 14.4 Plan Update Lewis County intends to update the Comprehensive Flood Hazard Management Plan on a five-year cycle from the date of initial plan adoption (CRS Step 10).This cycle may be accelerated to less than five-years based on the following triggers: • A Presidential Disaster Declaration that impacts the planning area. 139 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T • A flood hazard event that causes loss of life. • An update of Lewis County Comprehensive Plan. It will not be the intent of future updates to develop a completely new Comprehensive Flood Hazard Management Plan for the planning area.The update will, at a minimum, include the following elements: • The update process will be convened through a Stakeholder Committee. • The hazard risk assessment will be reviewed and, if necessary, updated using best available information and technologies. • The action plan will be reviewed and revised to account for any actions completed, dropped, or changed and to account for changes in the risk assessment or new policies identified under other planning mechanisms (such as the comprehensive plan). • The draft update will be sent to appropriate agencies and organizations for comment. • The public will be given an opportunity to comment on the update prior to adoption. • The Lewis County Board of County Commissioners will adopt the updated plan. It is Lewis County's intention to fully integrate this Comprehensive Flood Hazard Management Plan into the Natural Hazards Mitigation Plan for Lewis County at some time.This will allow for a uniform update cycle for both plans and eliminate redundant planning. 14.5 Continuing Public Involvement The public will continue to be apprised of the plan's progress through the Flood Control Zone District website and by providing copies of annual progress reports to the media.The website will not only house the final plan, it will become the one-stop shop for information regarding the Flood Plan and plan implementation. Upon initiation of future update processes, a new public involvement strategy will be initiated based on guidance from the Stakeholder Committee.This strategy will be based on the needs and capabilities of Lewis County at the time of the update.At a minimum, this strategy will include the use of local media outlets within the planning area. 14.6 Incorporation into Other Planning Mechanisms The information on hazard, risk, vulnerability, and mitigation contained in this plan is based on the best science and technology available at the time this plan was prepared.The Lewis County Comprehensive Plan is an integral part of this plan. Lewis County,through adoption of a comprehensive plan and zoning ordinance, has planned for the impact of flooding. The Flood Plan development process provided the opportunity to review and expand on policies in these planning mechanisms. Lewis County's Comprehensive Plan and the Chehalis River Basin Comprehensive Flood Hazard Management Plan are complementary documents that work together to achieve the goal of reducing flood-risk exposure.An update to the county's comprehensive plan may trigger an update to the Comprehensive Flood Hazard Management Plan. Lewis County has identified a priority action to link the Comprehensive Flood Hazard Management Plan and Lewis County Comprehensive Plan and City plans.Other planning processes and programs to be coordinated with the recommendations of the Comprehensive Flood Hazard Management Plan include the following: 140 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T • Lewis County Multi-jurisdictional Hazard Mitigation Plan • Emergency response plans • Capital improvement programs • Municipal codes • Community design guidelines • Stormwater management programs • Water system vulnerability assessments Some action items do not need to be implemented through regulation. Instead,these items can be implemented through the creation of new educational programs, continued interagency coordination, or improved public participation.As information becomes available from other planning mechanisms that can enhance this plan,that information will be incorporated via the update process. 141 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T 15.0 REFERENCES Army Corps of Engineers (2002). Centralis Flood Damage Reduction Project; Chehalis River, Washington; General Reevaluation Study. US Army Corps of Engineers, Seattle District.July 2002. Army Corps of Engineers (2021). National Levee Database.Accessed online at: https://levees.sec.usace.army.mil/# The Chronicle (2015). Flood Central: All Local Rivers Have Crested, Receding. December 10, 2015. Accessed online at: https://www.chronline.com/stories/flood-central-all-local-rivers-have-crested- receding,66389 City of Centralia (2008). Comprehensive Flood Management and Natural Hazards Mitigation Plan. December 9, 2008. Dalton, M.M., P.W. Mote, and A.K. Snover [Eds.] (2013). Climate Change in the Northwest: Implications for Our Landscapes,Waters, and Communities. Washington, DC: Island Press. Accessed online at: http://cses.washington.edu/db/pdf/snoveretalsok2013sec2.pdf Environmental Protection Agency(EPA) (2016). Climate Change Indicators in the United States. The website of the EPA. Last updated August 11, 2016.Accessed online at: https://www.epa.gov/climate- indicators/climate-change-indicators-atmospheric-concentrations-greenhouse-gases Environmental Protection Agency(EPA) (2021).Toxic Release Inventory Program.Accessed online at: https://www.epa.gov/toxics-release-inventory-tri-program Federal Emergency Management Agency(FEMA) (2006). Lewis County, Washington Flood Insurance Study.July 17, 2006. Federal Emergency Management Agency(FEMA) (2017). National Flood Insurance Program, Community Rating System; CRS Coordinator's Manual FIA-15/2017 OMB No. 1660-0022. Federal Emergency Management Agency(FEMA) (2021a). Disaster Declarations for States and Counties. Accessed online at: https://www.fema.gov/data-visualization/disaster-declarations-states-and-counties Federal Emergency Management Agency(FEMA) (2021b). National Flood Insurance Program, Community Rating System; Addendum to the 2017 CRS Coordinator's Manual. Federal Emergency Management Agency(FEMA) (2021c). National Flood Insurance Program, Lewis County Flood Insurance Statistics. Provided by Scott Van Hoff. May 23, 2021. Federal Emergency Management Agency (FEMA) (2021d). Personal communication with Dwight Perkins. June 3, 2021. Fountain, Henry(2020). 'Expect More': Climate Change Raises Risk of Dam Failure. New York Times. May 21, 2020.Accessed online at: https://www.nytimes.com/2020/05/21/climate/dam-failure-michigan- climate-change.html 142 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Herrera Environmental Consultants,AHBL, and CORE GIS (2013). Shoreline Inventory and Characterization Report for Lewis County and the Cities of Centralia, Chehalis, Morton, and Winlock. October 17, 2013. Huang, X., Hall, A.D., & Berg, N. (2018). Anthropogenic warming impacts on today's Sierra Nevada snowpack and flood risk. Geophysical Research Letters, 45, 6215-6222.Accessed online at: https://doi.org/10.1029/2018GL077432 Intergovernmental Panel on Climate Change (IPCC) (2014). Climate Change 2014: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Parts A, B and Annexes.Accessed online at: http://www.ipcc.ch/report/ar5/wg2/ King, Rawle (2005). Federal Flood Insurance:The Repetitive Loss Problem. CRS Report for Congress.June 30, 2005. Lewis County Conservation District (1992). Chehalis River Basin Action Plan --Technical Supplement. Chehalis, Washington. October 1992. Lewis County(2008). Comprehensive Flood Hazard Management Plan for Lewis County, September, 2008. Lewis County (2009a). December 3, 2007 Chehalis River Flooding Event Description. Accessed online at: https://www.ezview.wa.gov/Portals/ 1492/images/default/DECEMBER%203%20FIood%200ne- Yea r%20Later%2011-20-08.pdf Lewis County(2009b). Lewis County 2007 Flood Disaster Recovery Strategy. April 2009. Lewis County(2016). Lewis County Multi-Jurisdictional Hazard Mitigation Plan. Prepared by Lewis County Emergency Management.January 6, 2016. Mauger, G.S., S.-Y. Lee, C. Bandaragoda, Y. Serra,J.S. Won (2016). Effect of Climate Change on the Hydrology of the Chehalis Basin. Report prepared for Anchor QEA, LLC. Climate Impacts Group, University of Washington,Seattle. Mauger, G. (2021). Chehalis Basin: Extreme Precipitation Projections. Climate Impact Group, University of Washington, Seattle. February 4, 2021. McDonald,Julie, and Edna Fund (2007). From Native American Legends to 2007: A History of Flooding in the Chehalis River Basin. Chronicle Online. Accessed online at: http://www.chronline.com/from-native- american-legends-to-a-history-of-flooding-in/article 5907dba8-dad4-11e7-9643-5b146dd7cbcb.html McNamara,A. (2020). Magnitude of Late Century Flood for Local Actions Program. Memo to the Chehalis Basin Board. November 30, 2020. Melillo,Jerry M.,Terese (T.C.) Richmond, and Gary W.Yohe, Eds (2014). Climate Change Impacts in the United States:The Third National Climate Assessment. U.S. Global Change Research Program. 143 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RT E E T Mote, P., A. K. Snover, S. Capalbo, S. D. Eigenbrode, P. Glick,J. Littell, R. Raymondi, and S. Reeder(2014). Ch. 21: Northwest. Climate Change Impacts in the United States:The Third National Climate Assessment, J. M. Melillo,Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program,487- 513. doi:10.7930/J04Q7RWX. National Aeronautics and Space Administration (NASA) (2016). Global Climate Change:Vital Signs of the Planet.The website of NASA. Last updated April 3, 2021.Accessed online at: https://climate.nasa.gov/ National Aeronautics and Space Administration (NASA) (2021). Potent Atmospheric Rivers Douse the Pacific Northwest.Accessed online at: https://earthobservatory.nasa.gov/images/147822/potent- atmospheric-rivers-douse-the-pacific-northwest National Weather Service (NWS) (2021). Advanced Hydrologic Prediction Service for Chehalis River. Accessed online at: https://water.weather.gov/ahps2/glance.php?wfo=sew&gage=dotwl&riverid=203552 Office of Financial Management(OFM) (2021). Components of Population Change.Accessed online at: https://ofm.wa.gov/washington-data-research/population-demographics/population- estimates/components-population-change Office of Financial Management(OFM) (2017). Growth Management Act Population Projections for Counties: 2010 to 2040.Accessed online at: https://ofm.wa.gov/washington-data-research/population- demographics/population-forecasts-and-projections/growth-management-act-county- proiections/growth-management-act-population-projections-counties-2010-2040-0 Office of Financial Management(OFM) (2019). Lewis County Databook.Accessed online at: https://ofm.wa.gov/sites/default/files/public/dataresearch/databook/pdf/53041.pdf Ruckelshaus Center(2012). Chehalis Basin Flood Hazard Mitigation Alternatives Report. December 19, 2012. Rukelshaus Center(2014). Governor's Chehalis Basin Work Group 2014 Recommendations Report. November 2014. Rufat,Samuel, Eric Tate, Christopher G. Burton, and Abu Sayeed Maroof(2015). "Social vulnerability to floods: Review of case studies and implications for measurement." International Journal of Disaster Risk Reduction 14 (2015)470-486. Accessed online at: http://www.sciencedirect.com/science/journal/22124209/14/part/P4?sdc=1 Sarikhan, Isabelle Y., Kelsay Davis Stanton,Trevor A. Contreras, Michael Polenz,Jack Powell,Timothy J. Walsh, and Robert L. Logan (2008). Landslide Reconnaissance Following the Storm Event of December 1- 3, 3007 in Western Washington. Department of Natural Resources. Open File Report 2008-5. November 2008.Accessed online at: https://www.dnr.wa.gov/Publications/ger ofr2008-5 dec2007 landslides.pdf US Census (2019). Lewis County Profile.Accessed online at: https://data.census.gov/cedsci/al I?q=lewis%20county,%20wa&tid=ACSDP1Y2019.DP05 144 NOVEMBER 2021 I COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN P E RTE E T Washington State Department of Ecology(WA Ecology) (2020). Chehalis Basin Strategy State Environmental Policy Act Draft Environmental Impact Statement; Proposed Chehalis River Basin Flood Damage Reduction Project. Publication #20-06-002. February 27, 2020. Washington State Department of Ecology(WA Ecology) (2017). Chehalis Basin Strategy Final Programmatic Environmental Impact Statement (EIS). Publication#17-06-017.June 2, 2017. Washington State Department of Ecology(WA Ecology) (2020). Inventory of Dams Report. Publication #94-16. September 11, 2020. Washington State Employment Security Department(ESD) (2021). Lewis County Labor Market Information. Accessed online at: https://esd.wa.gov/labormarketinfo/lewis Washington State Department of Fisheries (1975).A Catalog of Washington Streams and Salmon Utilization,Vol. 1: Puget Sound. Olympia,WA. Washington State Department of Natural Resources(DNR) (2017). Fact Sheet: What are Landslides? April 11, 2017.Accessed online at: https://www.dnr.wa.gov/publications/ger fs landslide processes.pdf WATERSHED Science & Engineering and WEST Consultants (2012). Draft Report—Chehalis River Hydraulic Model Development Project.July 23, 2012. Western Washington University(WWU), Center of Economic and Business Research (2019). Lewis County Economic Profile.Accessed online at: https://www.chamberway.com/wp- content/uploads/Profile-Lewis 6-26-19 web-1.pdf Washington State University(WSU) (2007). Flood-dampened hay poses fire risk. December 14, 2007. Accessed online at: https://news.wsu.edu/2007/12/14/flood-dampened-hay-poses-fire-risk/ Yaw, Claudia (2020).The Chronicle. Chehalis Superfund Site Deleted From EPA's National Priority List. Accessed online at: https://www.chronline.com/stories/chehalis-superfund-site-deleted-from-epas- national-priority-list,873 145 APPENDIX A Relevant Programs and Regulations 1.0 RELEVANT PROGRAMS AND REGULATIONS Existing laws, ordinances and plans at the federal, state, and local level can support or impact flood hazard mitigation actions identified in this plan. Flood hazard mitigation planning typically includes review and incorporation as appropriate of existing plans, studies, and technical information.This section provides a review of laws and ordinances that can affect flood hazard mitigation in the planning area. Some laws and programs have emergency protocols that go into effect during emergency situations to waive or expedite requirements or procedures.These modifications are limited in scope and duration, and all mitigation and recovery projects should be planned for and implemented in ways that they meet all federal, state, and local laws. All the following federal, state and local programs have been identified as being related to the goals and objectives to this plan. 1.1 Federal 1.1.1 Disaster Mitigation Act of 2000 The federal Disaster Mitigation Act(DMA)of 2000 (Public Law 106-390) provides the legal basis for FEMA mitigation planning requirements for state, local and Indian tribal governments as a condition of mitigation grant assistance. The DMA amended the Robert T. Stafford Disaster Relief and Emergency Assistance Act by replacing previous mitigation planning provisions with new requirements that emphasize the need for planning entities to coordinate mitigation planning and implementation efforts. The law added incentives for increased coordination and integration of mitigation activities at the state level by establishing two levels of state plans.The DMA also established a new requirement for local mitigation plans and authorized up to 7 percent of Hazard Mitigation Grant Program funds to be available for development of state, local, and Indian tribal mitigation plans. 1.1.2 National Flood Insurance Program The NFIP makes federally backed flood insurance available to homeowners, renters, and business owners in participating communities that enact flood hazard management regulations. For most participating communities, FEMA has prepared a detailed Flood Insurance Study.The study presents water surface elevations for floods of various magnitudes, including the one-percent annual chance flood (100-year flood)and the 0.2-percent annual chance flood (the 500-year flood). Base flood elevations and the boundaries of the 100-and 500-year floodplains are shown on Flood Insurance Rate Maps (FIRMs),which are the principal tools for identifying the extent and location of the flood hazard. FIRMs are the most detailed and consistent data source available, and for many communities they represent the minimum area of oversight under their flood hazard management program. NFIP participants must, at a minimum, regulate development in floodplains in accordance with NFIP criteria. Before issuing a permit to build in a mapped flood area, participants must ensure that three criteria are met: • New buildings and those undergoing substantial improvements must, at a minimum, be elevated to protect against damage by the 100-year flood. • New floodplain development must not aggravate existing flood problems or increase damage to other properties. 1 • New floodplain development must exercise a reasonable and prudent effort to reduce its adverse impacts on threatened salmonid species. Lewis County participates in the NFIP, as do the cities of Chehalis and Centralia. All have adopted regulations that meet the NFIP requirements.Table 4-1 summarizes participation dates for these communities. Table 1-1. NFIP Participation by Lewis County and Municipalities. Initial Flood Hazard Initial Flood Current Program Entry Insurance Rate Effective Map ID Community Name Boundary Map Date Map Date 530103 City of Centralia 03/15/74 06/01/82 06/01/82 06/01/82 530104 City of Chehalis 06/07/74 05/01/80 07/17/06 05/01/80 530254 City of Napavine 12/14/75 07/17/06 07/17/06 05/19/17 530296 Town of Pe Ell 07/18/75 03/04/80 03/04/80 03/04/80 530102 Lewis County 11/29/77 12/15/81 07/17/06 12/15/81 Source: FEMA Structures permitted or constructed in participating communities before the first FIRM was adopted are called "pre-FIRM" structures, and structures built afterwards are called "post-FIRM."The insurance rate is different for the two types of structures.The effective date for the current FIRM is September 30, 2004.At the time of this planning process, FEMA was in the process of updating Lewis County's maps, but no progress has been made for several years. Lewis County is currently in good standing with the provisions of the NFIP. 1.1.3 The Community Rating System The CRS is a voluntary program within the NFIP that encourages flood hazard management activities that exceed the minimum NFIP requirements. Flood insurance premiums are discounted in participating communities to reflect the reduced flood risk resulting from community actions to meet the CRS goals of reduce and avoid flood damage to insurable property, strengthen and support the insurance aspects of the NFIP and foster comprehensive floodplain management. For participating communities, flood insurance premium rates are discounted in increments of five percent. For example, a Class 1 community would receive a 45 percent premium discount, and a Class 9 community would receive a five percent discount. (Class 10 communities are those that do not participate in the CRS; they receive no discount.)The CRS classes for local communities are based on 19 creditable activities in the following categories: • Public information • Mapping and regulations • Flood damage reduction • Flood preparedness CRS activities can help to save lives and reduce property damage. Communities participating in the CRS represent a significant portion of the nation's flood risk; over 67 percent of the NFIP's policy base is in 2 these communities. Communities receiving premium discounts through the CRS range from small to large and represent a broad mixture of flood risks, including riverine, shallow and flash flood risks. Figure 1-1. CRS Ratings as of June 1,2021. Community Name CRS Entry Date CRS Class SFHA Discount Non-SFHA Discount City of Centralia 10/1/1994 6 20% 10% City of Chehalis 10/1/1994 7 15% 5% City of Napavine - - - - TownofPeEll - - - - Lewis County 10/1/1994 5 25% 10% Source: FEMA 1.1.4 Endangered Species Act The federal Endangered Species Act(ESA)was enacted in 1973 to conserve species facing depletion or extinction and the ecosystems that support them.The act sets forth a process for determining which species are threatened and endangered and requires the conservation of the critical habitat in which those species live.The ESA provides broad protection for species of fish,wildlife and plants that are listed as threatened or endangered. Provisions are made for listing species,as well as for recovery plans and the designation of critical habitat for listed species. The ESA outlines procedures for federal agencies to follow when taking actions that may jeopardize listed species and contains exceptions and exemptions. It is the enabling legislation for the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Criminal and civil penalties are provided for violations of the ESA and the Convention. Federal agencies must seek to conserve endangered and threatened species and use their authorities in furtherance of the ESA's purposes.The ESA defines three fundamental terms: • Endangered means that a species of fish, animal or plant is "in danger of extinction throughout all or a significant portion of its range." (For salmon and other vertebrate species,this may include subspecies and distinct population segments.) • Threatened means that a species "is likely to become endangered within the foreseeable future." Regulations may be less restrictive for threatened species than for endangered species. • Critical habitat means "specific geographical areas that are...essential for the conservation and management of a listed species,whether occupied by the species or not." • Five sections of the ESA are of critical importance to understanding it: o Section 4: Listing of a Species—The National Oceanic and Atmospheric Administration Fisheries Service (NOAA Fisheries) is responsible for listing marine species;the US Fish and Wildlife Service is responsible for listing terrestrial and freshwater aquatic species.The agencies may initiate reviews for listings,or citizens may petition for them. A listing must be made "solely on the basis of the best scientific and commercial data available."After a listing has been proposed, agencies receive comment and conduct further scientific reviews for 12 to 18 months, after which they must decide if the listing is warranted. Economic impacts cannot be considered in this decision, but it may include an evaluation of the adequacy of local and state protections. Critical habitat for the species may be designated at the time of listing. 3 o Section 7: Consultation—Federal agencies must ensure that any action they authorize,fund, or carry out is not likely to jeopardize the continued existence of a listed or proposed species or adversely modify its critical habitat.This includes private and public actions that require a federal permit. Once a final listing is made, non-federal actions are subject to the same review,termed a "consultation." If the listing agency finds that an action will "take" a species, it must propose mitigations or"reasonable and prudent" alternatives to the action; if the proponent rejects these,the action cannot proceed. o Section 9: Prohibition of Take—It is unlawful to "take" an endangered species, including killing or injuring it or modifying its habitat in a way that interferes with essential behavioral patterns, including breeding, feeding or sheltering. o Section 10: Permitted Take—Through voluntary agreements with the federal government that provide protections to an endangered species, a non-federal applicant may commit a take that would otherwise be prohibited as long as it is incidental to an otherwise lawful activity(such as developing land or building a road).These agreements often take the form of a "Habitat Conservation Plan." o Section 11: Citizen Lawsuits—Civil actions initiated by any citizen can require the listing agency to enforce the ESA's prohibition of taking or to meet the requirements of the consultation process. • With the listing of salmon and trout species as threatened or endangered,the ESA has impacted most of the Pacific Coast states.Although some of these areas have been more impacted by the ESA than others due to the known presence of listed species,the entire region has been impacted by mandates, programs and policies based on the presumption of the presence of listed species. Most West Coast jurisdictions must now consider the impact of their programs on habitat. 1.1.5 The Clean Water Act The federal Clean Water Act (CWA) employs regulatory and non-regulatory tools to reduce direct pollutant discharges into waterways,finance municipal wastewater treatment facilities, and manage polluted runoff.These tools are employed to achieve the broader goal of restoring and maintaining the chemical, physical, and biological integrity of the nation's surface waters so that they can support"the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water." Evolution of CWA programs over the last decade has included a shift from a program-by-program, source-by-source, pollutant-by-pollutant approach to more holistic watershed-based strategies. Under the watershed approach, equal emphasis is placed on protecting healthy waters and restoring impaired ones.A full array of issues are addressed, not just those subject to CWA regulatory authority. Involvement of stakeholder groups in the development and implementation of strategies for achieving and maintaining water quality and other environmental goals is a hallmark of this approach. 1.1.6 National Environmental Policy Act The National Environmental Policy Act(NEPA) requires federal agencies to consider the environmental impacts of proposed actions and reasonable alternatives to those actions, alongside technical and economic considerations. NEPA established the Council on Environmental Quality, whose regulations (40 CFR Parts 1500-1508) set the standard for NEPA compliance. Consideration of environmental impacts and decision-making process is documented in an environmental impact statement or 4 environmental assessment. Environmental impact assessment requires the evaluation of reasonable alternatives to a proposed action, solicitation of input from organizations and individuals that could be affected, and the unbiased presentation of direct, indirect, and cumulative environmental impacts. 1.1.7 National Incident Management System The National Incident Management System (NIMS) is a systematic approach for government, nongovernmental organizations, and the private sector to work together to manage incidents involving floods and other hazards.The NIMS provides a flexible but standardized set of incident management practices. Incidents typically begin and end locally, and they are managed at the lowest possible geographical, organizational, and jurisdictional level. In some cases, success depends on the involvement of multiple jurisdictions, levels of government,functional agencies, and emergency- responder disciplines.These cases necessitate coordination across this spectrum of organizations. Communities using NIMS follow a comprehensive national approach that improves the effectiveness of emergency management and response personnel across the full spectrum of potential hazards (including natural hazards,terrorist activities, and other human-caused disasters) regardless of size or complexity. 1.1.8 Americans with Disabilities Act The Americans with Disabilities Act(ADA) seeks to prevent discrimination against people with disabilities in employment,transportation, public accommodation, communications, and government activities. Title II of the ADA deals with compliance with the Act in emergency management and disaster-related programs, services, and activities. It applies to state and local governments as well as third parties, including religious entities and private nonprofit organizations. The ADA has implications for sheltering requirements and public notifications. During an emergency, officials must use a combination of warning methods to ensure that all residents have any necessary information.Those with hearing impairments may not hear radio,television,sirens, or other audible alerts,while those with visual impairments may not see flashing lights or visual alerts.Two technical documents issued for shelter operators address physical accessibility needs of people with disabilities as well as medical needs and service animals. The ADA intersects with disaster preparedness programs in regard to transportation,social services, temporary housing, and rebuilding. Persons with disabilities may require additional assistance in evacuation and transit (e.g.,vehicles with wheelchair lifts or paratransit buses). Evacuation and other response plans should address the unique needs of residents. Local governments may be interested in implementing a special-needs registry to identify the home addresses, contact information, and needs for residents who may require more assistance. 1.1.9 Civil Rights Act of 1964 The Civil Rights Act of 1964 prohibits discrimination based on race, color, religion, sex, or national origin and requires equal access to public places and employment.The Act is relevant to emergency management and hazard mitigation in that it prohibits local governments from favoring the needs of one population group over another. 5 Local government and emergency response must ensure the continued safety and well-being of all residents equally,to the extent possible. 1.1.10 Rural Development Program The mission of the US Department of Agriculture (USDA) Rural Development Program is to help improve the economy and quality of life in rural America.The program provides project financing and technical assistance to help rural communities provide the infrastructure needed by rural businesses, community facilities, and households.The program addresses rural America's need for basic services, such as clean running water, sewage and waste disposal, electricity, and modern telecommunications and broadband. Loans and competitive grants are offered for various community and economic development projects and programs, such as the development of essential community facilities including fire stations. 1.1.11 Community Development Block Grant Disaster Resilience Program In response to disasters, Congress may appropriate additional funding for the US Department of Housing and Urban Development Community Development Block Grant programs to be distributed as Disaster Recovery grants(CDBG-DR).These grants can be used to rebuild affected areas and provide seed money to start the recovery process. CDBG-DR assistance may fund a broad range of recovery activities, helping communities and neighborhoods that otherwise might not recover due to limited resources. CDBG-DR grants often supplement disaster programs of the Federal Emergency Management Agency,the Small Business Administration, and the US Army Corps of Engineers. Housing and Urban Development generally awards noncompetitive, nonrecurring CDBG-DR grants by a formula that considers disaster recovery needs unmet by other federal disaster assistance programs.To be eligible for CDBG-DR funds, projects must meet the following criteria: • Address a disaster-related impact(direct or indirect) in a federally declared county • Be a CDBG-eligible activity(according to regulations and waivers) • Meet a national objective Incorporating preparedness and mitigation into these actions is encouraged, as the goal is to rebuild in ways that are safer and stronger. 1.1.12 Emergency Watershed Program The USDA Natural Resources Conservation Service(NRCS) administers the Emergency Watershed Protection (EWP) Program, which responds to emergencies created by natural disasters. Eligibility for assistance is not dependent on a national emergency declaration.The program is designed to help people and conserve natural resources by relieving imminent hazards to life and property caused by floods,fires,windstorms, and other natural occurrences. EWP is an emergency recovery program. Financial and technical assistance are available for the following activities: • Remove debris from stream channels, road culverts, and bridges • Reshape and protect eroded banks • Correct damaged drainage facilities • Establish cover on critically eroding lands • Repair levees and structures • Repair conservation practices (National Resources Conservation Service, 2016) 6 1.1.13 Presidential Executive Orders 11988 and 13690 Executive Order 11988 requires federal agencies to avoid to the extent possible the long and short-term adverse impacts associated with the occupancy and modification of floodplains and to avoid direct and indirect support of floodplain development wherever there is a practicable alternative. It requires federal agencies to provide leadership and take action to reduce the risk of flood loss, minimize the impact of floods on human safety, health, and welfare, and restore and preserve the natural and beneficial values of floodplains.The requirements apply to the following activities (FEMA, 2015d): • Acquiring, managing, and disposing of federal lands and facilities • Providing federally undertaken,financed, or assisted construction and improvements • Conducting federal activities and programs affecting land use, including but not limited to water and related land resources planning, regulation, and licensing. Executive Order 13690 expands Executive Order 11988 and acknowledges that the impacts of flooding are anticipated to increase over time due to the effects of climate change and other threats. It mandates a federal flood risk management standard to increase resilience against flooding and help preserve the natural values of floodplains.This standard expands management of flood issues from the current base flood level to a higher vertical elevation and corresponding horizontal floodplain when federal dollars are involved in a project.The goal is to address current and future flood risk and ensure that projects funded with taxpayer dollars last as long as intended (Office of the Press Secretary, 2015). 1.1.14 Presidential Executive Order 11990 Executive Order 11990 requires federal agencies to provide leadership and take action to minimize the destruction, loss,or degradation of wetlands, and to preserve and enhance the natural and beneficial values of wetlands.The requirements apply to the following activities (National Archives, 2016): • Acquiring, managing, and disposing of federal lands and facilities • Providing federally undertaken,financed,or assisted construction and improvements • Conducting federal activities and programs affecting land use, including but not limited to water and related land resources planning, regulation, and licensing. 1.1.15 Emergency Relief for Federally Owned Roads Program The US Forest Service's Emergency Relief for Federally Owned Roads Program was established to assist federal agencies with repair or reconstruction of tribal transportation facilities, federal lands transportation facilities, and other federally owned roads that are open to public travel and have suffered serious damage by a natural disaster over a wide area or by a catastrophic failure.The program funds both emergency and permanent repairs(Office of Federal Lands Highway, 2016). 1.1.16 US Army Corps of Engineers Programs The US Army Corps of Engineers has several civil works authorities and programs related to flood risk and flood hazard management: • Floodplain Management Services are 100-percent federally funded technical services such as development and interpretation of site-specific data related to the extent, duration, and frequency of flooding. Special studies may be conducted to help a community understand and respond to flood risk.These may include flood hazard evaluation,flood warning and preparedness, or flood modeling. 7 • For more extensive studies,the Corps of Engineers offers a cost-shared program called Planning Assistance to States and Tribes. Studies under this program generally range from $25,000 to $100,000 with the local jurisdiction providing 50 percent of the cost. • The Corps of Engineers has several cost-shared programs (typically 65 percent federal and 35 percent non-federal) aimed at developing,evaluating, and implementing structural and non- structural capital projects to address flood risks at specific locations or within a specific watershed: o The Continuing Authorities Program for smaller-scale projects includes Section 205 for Flood Control, with a $7 million federal limit and Section 14 for Emergency Streambank Protection with a o $1.5 million federal limit. These can be implemented without specific authorization from Congress. o Larger scale studies, referred to as General Investigations, and projects for flood risk management,for ecosystem restoration or to address other water resource issues, can be pursued through a specific authorization from Congress and are cost-shared,typically at 65 percent federal and 35 percent non-federal. o Watershed Management planning studies can be specifically authorized and are cost-shared at 50 percent federal and 50 percent non-federal. • The Corps of Engineers provides emergency response assistance during and following natural disasters. Public Law 84-99 enables the Corps to assist state and local authorities in flood fight activities and cost share in the repair of flood protective structures. Assistance afforded under PL 84-99 is broken down into the following three categories: o Preparedness—The Flood Control and Coastal Emergency Act establishes an emergency fund for preparedness for emergency response to natural disasters;for flood fighting and rescue operations; for rehabilitation of flood control and hurricane protection structures. Funding for Corps of Engineers emergency response under this authority is provided by Congress through the annual Energy and Water Development Appropriation Act. Disaster preparedness activities include coordination, planning,training and conduct of response exercises with local, state, and federal agencies. o Response Activities—PL 84-99 allows the Corps of Engineers to supplement State and local entities in flood fighting urban and other non-agricultural areas under certain conditions (Engineering Regulation 500-1-1 provides specific details).All flood fight efforts require a Project Cooperation Agreement signed by the public sponsor and a requirement for the sponsor to remove all flood fight material after the flood has receded. PL 84-99 also authorizes emergency water support and drought assistance in certain situations and allows for"advance measures" assistance to prevent or reduce flood damage conditions of imminent threat of unusual flooding. o Rehabilitation—Under PL 84-99, an eligible flood protection system can be rehabilitated if damaged by a flood event.The flood system would be restored to its pre-disaster status at no cost to the Federal system owner, and at 20%cost to the eligible non-Federal system owner. All systems considered eligible for PL 84-99 rehabilitation assistance must be in the Rehabilitation and Inspection Program (RIP) prior to the flood event.Acceptable operation and maintenance by the public levee sponsor are verified by levee inspections conducted by the Corps on a regular basis.The Corps has the responsibility to coordinate levee repair issues with interested Federal, State, and local agencies following natural disaster events where flood control works are damaged. 8 1.2 State 1.2.1 Washington State Floodplain Management Law Washington's floodplain management law(Revised Code of Washington (RCW) 86.16, implemented through Washington Administrative Code (WAC) 173-158)states that prevention of flood damage is a matter of statewide public concern and places regulatory control with the Department of Ecology. RCW 86.16 is cited in floodplain management literature, including FEMA's national assessment, as one of the first and strongest in the nation. A 1978 major challenge to the law—Maple Leaf Investors Inc.v. Department of Ecology—is cited in legal references to flood hazard management issues. The court upheld the law, declaring that denial of a permit to build residential structures in the floodway is a valid exercise of police power and did not constitute a taking. RCW Chapter 86.12 (Flood Control by Counties) authorizes county governments to levy taxes, condemn properties and undertake flood control activities directed toward a public purpose. 1.2.2 Department of Ecology Grants Washington's first flood control maintenance program, passed in 1951,was called the Flood Control Maintenance Program. In 1984,the state Legislature established the Flood Control Assistance Account Program (FCAAP)to assist local jurisdictions in comprehensive planning and flood control maintenance (RCW 86.26; WAC 173-145).This is one of the few state programs in the country that provides grant funding to local governments for flood hazard management planning and implementation.The account is funded at$4 million per state biennium, unless modified by the Legislature. Projects include comprehensive flood hazard management planning, maintenance projects, feasibility studies, purchase of flood-prone properties, matches for federal projects, and emergency projects. Funding is available in the FCAAP for the first time in several years for the 2021-2023 biennium and is anticipated to be funded into the future. In 2013, the Legislature authorized $44 million in new funding for integrated projects consistent with Floodplains by Design, an emerging partnership of local,state,federal and private organizations focused on coordinating investment in and strengthening the integrated management of floodplain areas. The most recent funding for the 2019-2021 biennium totaled $50.4 million.The Department of Ecology's Floods and Floodplain Management Division administers the Floodplains by Design grant program. Ecology awards grants on a competitive basis to eligible entities for collaborative and innovative projects in Washington that support the integration of flood hazard reduction with ecological preservation and restoration. Proposed projects may also address other community needs, such as preservation of agriculture, improvements in water quality,or increased recreational opportunities, provided they are part of a larger strategy to restore ecological functions and reduce flood hazards. 1.2.3 Shoreline Management Act The 1971 Shoreline Management Act (RCW 90.58)was enacted to manage and protect the shorelines of the state by regulating development in the shoreline area. A major goal of the act is to prevent the "inherent harm in an uncoordinated and piecemeal development of the state's shorelines." Its jurisdiction includes all water areas of the state, including reservoirs, and their associated shorelands, together with the lands underlying them, except: shorelines of statewide significance; streams upstream of where the mean annual flow is 20 cubic feet per second or less; and lakes smaller than 20 acres. 9 1.2.4 Growth Management Act The 1990 Washington State Growth Management Act(RCW Chapter 36.70A) mandates that local jurisdictions adopt land use ordinances to protect the following critical areas: • Wetlands • Critical aquifer recharge areas • Fish and wildlife habitat conservation areas • Frequently flooded areas • Geologically hazardous areas The Growth Management Act regulates development in these areas, and therefore has the potential to affect hazard vulnerability and exposure at the local level. 1.2.5 Washington State Building Code The Washington State Building Code Council adopted the 2018 editions of national model codes,with some amendments (RCW 19.27.074).The Council also adopted changes to the Washington State Energy Code. Washington's state-developed codes are mandatory statewide for residential and commercial buildings. The residential code exceeds the 2006 International Energy Conservation Code standards (as amended) for most homes, and the commercial code meets or exceeds standards of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE 90.1-2004). For residential construction covered by ASHRAE 90.1- 2007 (buildings with four or more stories),the state code is more stringent. The 2018 International Building Code went into effect as the Washington model code on February 1, 2021. 1.2.6 Comprehensive Emergency Management Planning Washington's Comprehensive Emergency Management Planning law(RCW 38.52) establishes parameters to ensure that preparations of the state will be adequate to deal with disasters,to ensure the administration of state and federal programs providing disaster relief to individuals,to ensure adequate support for search and rescue operations,to protect the public peace, health and safety, and to preserve the lives and property of the people of the state. It achieves the following: • Provides for emergency management by the state and authorizes the creation of local organizations for emergency management in political subdivisions of the state. • Confers emergency powers upon the governor and upon the executive heads of political subdivisions of the state. • Provides for the rendering of mutual aid among political subdivisions of the state and with other states and for cooperation with the federal government with respect to the carrying out of emergency management functions. • Provides a means of compensating emergency management workers who may suffer any injury or death,who suffer economic harm including personal property damage or loss, or who incur expenses for transportation,telephone or other methods of communication, and the use of personal supplies as a result of participation in emergency management activities. 10 • Provides programs, with intergovernmental cooperation,to educate and train the public to be prepared for emergencies. It is policy under this law that emergency management functions of the state and its political subdivisions be coordinated to the maximum extent with comparable functions of the federal government and agencies of other states and localities, and of private agencies of every type,to the end that the most effective preparation and use may be made of manpower, resources, and facilities for dealing with disasters. WAC 118-30-060(1) requires each political subdivision to base its comprehensive emergency management plan on a hazard analysis, and makes the following definitions related to hazards: • Hazards are conditions that can threaten human life as the result of three main factors: o Natural conditions, such as weather and seismic activity. o Human interference with natural processes, such as a levee that displaces the natural flow of floodwaters. o Human activity and its products, such as homes in a flood hazard area. • The definitions for hazard, hazard event, hazard identification, and flood hazard include related concepts: o A hazard may be connected to human activity. o Hazards are extreme events. Hazards generally pose a risk of damage, loss, or harm to people and/or their property. 1.2.7 Watershed Management Act Washington's Watershed Management Act of 1998 encourages local communities to develop plans for protecting local water resources and habitat. Lawmakers wanted local governments and citizens to develop plans since they know their own regions best. WRIA is an acronym for"Water Resource Inventory Area." WRIAs are watershed planning areas established by the Department of Ecology. Washington State is divided into 62 WRIAs, each loosely drawn around a natural watershed or group of watersheds.A watershed is an area of land that drains into a common river, lake, or the ocean. 1.2.8 Washington State Enhanced Mitigation Plan The 2018 Washington State Enhanced Hazard Mitigation Plan provides guidance for hazard mitigation throughout Washington (Washington Emergency Management Division, 2018).The plan identifies hazard mitigation goals, objectives. and actions for state government to reduce injury and damage from natural hazards. By meeting federal requirements for an enhanced state plan (44 CFR Parts 201.4 and 201.5),the plan allows the state to seek significantly higher funding from the Hazard Mitigation Grant Program following presidential declared disasters(20 percent of federal disaster expenditures vs. 15 percent with a standard plan). 1.2.9 Washington Silver Jackets The Washington Silver Jackets team was formed in 2010 and is a mix of federal and state agencies that work together to address flood risk priorities in the state. Federal agencies include the Corps of 11 Engineers, which facilitates coordination within the group, FEMA, the National Oceanic and Atmospheric Administration (NOAA), and the US Geological Survey(USGS). Participating state agencies include the Department of Ecology, the Emergency Management Division, and the Department of Transportation. The team's projects are intended to address state needs and improve flood risk management throughout the full flood life cycle (Silver Jackets, 2016). 1.2.10 Land and Water Conservation Fund Congress established the Land and Water Conservation Fund in 1965 and authorized the Secretary of the Interior to provide financial assistance to the states for the acquisition and development of public outdoor recreation areas.The Washington State Recreation and Conservation Office administers the program in Washington. Funding comes from a portion of federal revenue from selling and leasing offshore oil and gas resources. Eligible projects include land acquisition and development or renovation projects, such as natural areas and open space.The Washington State Recreation and Conservation Office administers the program (Washington State Recreation and Conservation Office, 2016a). 1.2.11 Salmon Recovery Fund In 1999,the Washington State Legislature created the Salmon Recovery Funding Board.The board provides grants to protect or restore salmon habitat. Funded projects may include activities that protect existing, high quality habitat for salmon or that restore degraded habitat to increase overall habitat health and biological productivity. Funding also is available for feasibility assessments to determine future projects and for other salmon related activities. Projects may include the actual habitat used by salmon and the land and water that support ecosystem functions and processes important to salmon (Washington State Recreation and Conservation Office, 2016b). 1.2.12 State Environmental Policy Act The State Environmental Policy Act(SEPA) provides a way to identify possible environmental impacts of governmental decisions.These decisions may be related to issuing permits for private projects, constructing public facilities, or adopting regulations, policies, or plans. Information provided during the SEPA review process helps agency decision-makers, applicants, and the public understand how a proposal will affect the environment.This information can be used to change a proposal to reduce likely impacts, or to condition or deny a proposal when adverse environmental impacts are identified.Actions identified in hazard mitigation plans are frequently subject to SEPA review requirements before implementation. Non-project actions are governmental actions involving decisions on policies, plans, or programs that contain standards controlling use or modification of the environment,or that will govern a series of connected actions. This includes, but is not limited to,the adoption or amendment of comprehensive plans (WAC 197-11-704(2)(b)). Adoption of the Comprehensive Flood Hazard Management Plan will have no probable significant adverse impact on the environment; therefore, an environmental impact statement will not be required under RCW 43.21C.030(2)(c). 12 1.2.13 State Hydraulic Code Washington's Hydraulic Code states that any person or government agency intending to undertake a hydraulic project shall, before commencing work, secure a Hydraulic Project Approval from the Washington Department of Fish and Wildlife verifying the adequacy of the proposed means for protecting fish (RCW 77.55.021 (1)).The code defines a hydraulic project as work that will use, divert, obstruct, or change the natural flow or bed of any salt or freshwaters of the state.Approval is required for projects at or waterward of the ordinary high-water line and for projects landward of the ordinary high-water line that are immediately adjacent to waters of the state. 1.2.14 Office of the Chehalis Basin In 2016, the Washington Legislature created the Office of the Chehalis Basin to administer legislative funding to implement the Chehalis Basin Strategy.The Office of the Chehalis Basin is located within the Department of Ecology. 1.2.15 Chehalis River Basin Flood Authority The Chehalis River Basin Flood Authority was created in 2008 after the major flood of 2007.The Flood Authority is made up of officials from the principal jurisdictions in the basin, including Grays Harbor, Lewis, and Thurston Counties, and Aberdeen, Bucoda,Centralia, Chehalis, Cosmopolis, Hoquiam, Montesano, Napavine, Oakville, and Pe Ell.This planning project was funded by the Flood Authority. 1.3 Local 1.3.1 Flood Control Zone District The Chehalis River Basin Flood Control Zone District(FCZD)was initiated by the Board of Lewis County Commissioners on February 14, 2011. RCW 86.15 enables the creation of such districts for the purpose of undertaking, operating, or maintaining flood control projects.Activities of the FCZD may include the following: • Flood warning and emergency response • Flood-proofing and elevation of structures • Property acquisition • Implementation of consistent development regulations that recognize the impacts of flooding • Basin-wide flood planning • Flood facility maintenance • Public education and outreach • Mapping and technical studies • Mechanisms for citizen inquiry and public assistance • Identification, engineering, and construction of capital projects to mitigate flood problems The purpose of the Chehalis River Basin FCZD is to address the continuing flooding problem associated with the Chehalis River.The objectives of the District include but are not limited to: reducing the risk 13 associated with flooding; preserving life, preventing damage to property; and protecting, preserving and conserving natural resources within the District. The Flood Control Zone District is sponsoring a major flood mitigation project identified as the Governor's Work Group Recommendation in the Chehalis River Basin Strategy.The recommendation would achieve flood damage reduction through implementation of a Flood Retention Facility and raising the Airport Levee. The Chehalis River Basin FCZD is not currently funded but is authorized to assess up to $0.50 per$1,000. Examples of 2016 levy rates in other FCZDs include $0.12980 per$1,000 in King County, $0.1344 per $1,000 in Whatcom County, $0.070054 per$1,000 in Kittitas County, $0.10 per$1,000 in Pierce County, $0.07 per$1,000 in Chelan County, and $0.08975 per$1,000 in Yakima County. The adopted Flood Plan will direct future operations of the Chehalis River Basin FCZD. 1.3.2 Comprehensive Plan Lewis County's Comprehensive Plan, updated in 2018, provides guidance about what residents hope to see in their community.Washington's 1990 Growth Management Act established specific goals and requirements for local comprehensive plans and development regulations.The County's Comprehensive Plan will be updated every eight years as required by the GMA. The next update will provide an opportunity to integrate the findings and recommendation of this Flood Plan into the updated Comprehensive Plan. 1.3.3 Emergency Management Plan The 2011 Comprehensive Emergency Management Plan is Lewis County's framework for response to a disaster or emergency. Several emergency support function documents provided as functional annexes to the basic plan outline general guidelines by which County organizations will carry out the responsibilities assigned in the plan.These emergency support function documents are consistent with FEMA's 2008 National Response Framework. The Comprehensive Emergency Management Plan details the authorities,functions, and responsibilities of local, state, and federal agencies in the event of emergency. It describes the processes of crisis and consequence management and how the integrated actions of local, state, and federal agencies establish a mutually cooperative environment for preparedness, prevention, response, and recovery activities. 1.3.4 Critical Areas Ordinance Washington's GMA requires cities and counties to adopt policies and development regulations based on the best available science to protect critical areas. Lewis County updated its Critical Areas Ordinance to comply with the GMA in 2018. Chapter 17.38 of Lewis County Code describes and defines setback requirements for the following critical areas: • Fish and wildlife habitat conservation areas • Wetland areas • Aquifer recharge areas 14 • Frequently flooded areas • Geologically hazardous areas 1.3.5 Shoreline Master Program Lewis County's current Shoreline Master Program was adopted by the Lewis County and the Washington Department of Ecology in 2017. Primary responsibility for administering this regulatory program is assigned to the County's Community Development Department, which has jurisdiction for permitting development on the state's shoreline within the County. 1.3.6 Voluntary Stewardship Program The Voluntary Stewardship Program is an optional, incentive-based approach to protecting critical areas while promoting agriculture.The program is allowed under the Growth Management Act as an alternative to traditional approaches to critical areas protection, such as "no touch" buffers. Lewis County is one of 27 counties that has opted into the Voluntary Stewardship Program. 15 APPENDIX B Description of CRS and FCAAP Planning Guidelines COMMUNITY RATING SYSTEM GUIDELINES The Community Rating System provides credit for a community-wide floodplain management plan that was prepared by following a standard planning process.The plan must follow the ten steps listed below to receive full credit. Required items are shown in bold. Step 1. Organize to prepare the plan (Maximum credit: 15 points) The credit Step 1 is the total of the following points,which are based on how the community organizes to prepare its floodplain management plan: (a) if the office responsible for the community's land use and comprehensive planning is actively involved in the floodplain management planning process. (b) if the planning process is conducted through a committee composed of staff from those community departments that have expertise or will be implementing the majority of the plan's recommendations. (c) if the planning process and/or the committee are formally created or recognized by action of the community's governing board. The plan document must discuss how it was prepared,who was involved in the planning process, and how the public was involved during the planning process. When a multi-jurisdictional plan is prepared, at least two representatives from each community seeking CRS credit must be involved on the planning committee that is credited under item (b), and at least one representative must attend every planning committee meeting. Step 2. Involve the public (Maximum credit: 120 points) The planning process must include an opportunity for the public to comment on the plan during the drafting stage and before plan approval.The term "public" includes residents, businesses, property owners, and tenants in the floodplain and other known hazard areas as well as other stakeholders in the community, such as such as developers and contractors, civic groups, environmental organizations, academia, non-profit organizations, major employers, and staff from other governmental agencies, such as a levee district, housing authority, Natural Resources Conservation Service, or the National Weather Service. The credit for this step is the total of the following points based on how the community involves the public during the planning process. (a) if the planning process is conducted through a planning committee that includes members of the public. If this is the same planning committee credited under Step 1, items (b) and (c), at least one half of the members must be representatives of the public, including residents, businesses, or property owners from the flood-prone areas.The committee must hold a sufficient number of meetings that involve the members in planning steps 4 through 8 (e.g., at least one meeting on each step). (b) if one or more public information meetings are held in the affected area(s)within the first two months of the planning process to obtain public input on the natural hazards, problems, and possible solutions. At least one meeting must be held separate from the planning committee meetings in item (a). 1 (c)for holding at least one public meeting to obtain input on the draft plan.The meeting must be at the end of the planning process, at least two weeks before submittal of the recommended plan to the community's governing body. (d) if other public information activities are implemented to explain the planning process and encourage input to the planner or planning committee. Step 3. Coordinate (Maximum credit: 35 points) Other agencies and organizations must be contacted to see if they have any studies, plans, or information pertinent to the plan,to determine if they are doing anything that may affect the community's program, and to see if they could support the community's efforts. Examples of"other agencies and organizations" include neighboring communities; local, regional, state, and federal agencies; and businesses, academia, and other private and non-profit organizations affected by the hazards or involved in hazard mitigation or floodplain management.The credit for this step is the total of the following points.To receive credit for this step,the coordination must include items (a). (a) if the planning includes a review of existing studies,reports,and technical information and of the community's needs,goals,and plans for the area. (b)for coordinating with agencies and organizations outside the community's governmental structures. Coordinate means to contact the agency and keep a record, ask for data or information, ask if they are doing anything that might affect flooding, and offer opportunity to be involved in the planning effort. Step 4. Assess the hazard (Maximum credit: 35 points) Under this step,the community gathers data about natural hazards that affect the community.The credit for this step is the total of the following points based on what the community includes in its assessment of the hazard.To receive CRS credit for this step,the assessment must include item (a). If the community wants the plan to also qualify as a FEMA multi-hazard mitigation plan, item (b) must also be completed. (a)for including an assessment of the flood hazard in the plan. If the community is a Category B or C repetitive loss community,this step must cover all its repetitive loss areas.The assessment must include at least one of the following items: (1) a map of the known flood hazards. (2) a description of the known flood hazards, including source of water, depth of flooding,velocities, and warning time. (3)a discussion of past floods. (b)for including an assessment of less-frequent floods hazards.The assessment must: (1) identify the hazard such as preparing an inventory of levees or preparing and inventory of dams that would result in a flood of developed areas if they fail. (2) include a map of the area. (3)summarize the hazards in lay terms. (c)for including an assessment of flood problems that are likely to get worse in the future. (d)for including a description of the magnitude or severity, history, and probability of future events for other natural hazards, such as earthquakes,wildfires, or tornados.The plan should 2 include all-natural hazards that affect the community. At a minimum, it should include hazards identified by the state's hazard mitigation plan. Step 5. Assess the problem (Maximum credit: 52 points) In this step,the community collects data and summarizes what is at risk.The credit for this step is the total of the following points, based on what is included in the assessment of the vulnerability of the community to the hazards identified in the previous hazard assessment step.To receive credit for this step,the assessment must include item (a) and (c). (a) if the plan includes an overall summary of the jurisdiction's vulnerability to each hazard identified in the hazard assessment(Step 4)and the impact on the community. (b) if the plan includes a description of the impact that the hazards identified in the hazard assessment(Step 4) have on: life, safety, and public health; critical facilities and infrastructure; the community's economy and major employers;the number and types of affected buildings. (c) if the plan includes a review of historical damage to buildings, including all repetitive loss properties and all properties have received flood insurance claim payments. Category B and C repetitive loss communities must include their repetitive loss areas in their problem assessment. (d) if the plan describes areas that provide natural and beneficial functions, such as wetlands, riparian areas, sensitive areas, and habitat for rare or endangered species. (e) if the plan includes a description of development, redevelopment, and population trends and a discussion of what the future brings for development and redevelopment in the community, the watershed, and natural resource areas. (f) if the plan includes a description of the impact of the future flooding conditions described in item (c). Step 6. Set goals (Maximum credit: 2 points) The two credit points for this step are provided if the plan includes a statement of the goals of the community's floodplain management or hazard mitigation program.The goals must address all flood- related problems identified in Step 5. Step 7. Review possible activities (Maximum credit: 35 points) The plan must describe those activities that were considered and note why they were or were not recommended (e.g., they were not cost-effective, or they did not support the community's goals). If an activity is currently being implemented,the plan must note whether it should be modified.The discussion of each activity needs to be detailed enough to be useful to the lay reader.The credit for this step is the total of the following points based on which floodplain management or hazard mitigation activities are reviewed in the plan. (a) if the plan reviews preventive activities,such as zoning,stormwater management regulations, building codes,and preservation of open space and the effectiveness of current regulatory and preventive standards and programs. (b) if the plan reviews whether the community's floodplain management regulatory standards are sufficient for current and future conditions, as discussed under Steps 4(c) and 5(f) 3 (c) if the plan reviews property protection activities, such as acquisition, retrofitting, and flood insurance. (d) if the plan reviews activities to protect the natural and beneficial functions of the floodplain, such as wetlands protection. (e) if the plan reviews emergency services activities, such as warning and sandbagging. (f) if the plan reviews structural projects, such as reservoirs and channel modifications; and (g) if the plan reviews public information activities, such as outreach projects and environmental education programs. Step 8. Draft an action plan (Maximum credit: 60 points) The action plan specifies those activities appropriate to the community's resources, hazards, and vulnerable properties. For each recommendation, the action plan must identify who does what, when it will be done, and how it will be financed.The actions must be prioritized and include a review of the benefits of the proposed projects and their associated costs.A multi-jurisdictional plan must have actions from at least two of the following categories.The credit for this step is based on what is included in the action plan. Credit is provided for a recommendation on floodplain regulations, provided it recommends a regulatory standard that exceeds the minimum requirements of the NFIP. (a) how many categories credited in Step 7 have action items. (b) additional points are provided if the action plan establishes post-disaster mitigation policies and procedures. (c) additional points are provided if the plan includes action items (other than public information activities)to mitigate the effects of the other natural hazards identified in the hazard assessment(Step 4, item (b)). Step 9. Adopt the plan (Maximum credit: 2 points) The 2 credit points for this step are provided if the plan and later amendments are officially adopted by the community's governing body. When a multi-jurisdictional plan is prepared, it must be adopted by the governing board of each community seeking CRS or multi-hazard mitigation plan credit. Step 10. Implement, evaluate, and revise (Maximum credit: 26 points) The credit for this step is the total of the following points based on how the community monitors and evaluates its plan. (a) if the community has procedures for monitoring implementation, reviewing progress,and recommending revisions to the plan in an annual evaluation report.The report must be submitted to the governing body, released to the media,and made available to the public. (b) if the evaluation report is prepared by the same planning committee that prepared the plan that is credited in step 2(a) or by a successor committee with a similar membership that was created to replace the planning committee and charged with monitoring and evaluating implementation of the plan. 4 To maintain this credit, the community must submit a copy of its annual evaluation report with its recertification each year and update the plan at least every five years. FLOOD CONTROL ASSISTANCE ACCOUNT PROGRAM GUIDELINES Pursuant to WAC 173-145-040, a Comprehensive Flood Hazard Management Plan must include the following elements: 1) Determination of the need for flood control work. (a) Description of the watershed; (b) Identification of types of watershed flood problems; (c) Location and identification of specific problem areas; (d) Description of flood damage history; (e) Description of potential flood damage; (f) Short-term and long-term goals and objectives for the planning area; (g) Description of rules that apply within the watershed including, but not limited to, local shoreline management master programs, and zoning, subdivision, and flood hazard ordinances; (h) Determination that the in-stream flood control work is consistent with applicable policies and rules. 2) Alternative flood control work. (i) Description of potential measures of in-stream flood control work; (a) Description of alternatives to in-stream flood control work. 3) Identification and consideration of potential impacts of in-stream flood control work on the following in-stream uses and resources. (a) Fish resources; (b) Wildlife resources; (c) Scenic, aesthetic, and historic resources; (d) Navigation; (e) Water quality; (f) Hydrology; (g) Existing recreation; (h) Other impacts. 4) Area of coverage for the comprehensive plan shall include, as a minimum, the area of the one- hundred-year frequency flood plain within a reach of the watershed of sufficient length to ensure that a comprehensive evaluation can be made of the flood problems for a specific reach of the watershed.The plan may or may not include an entire watershed. Comprehensive plans shall also include flood hazard areas not subject to riverine flooding such as areas subject to coastal flooding,flash flooding, or flooding from inadequate drainage. Either the meander belt or floodway must be identified on aerial photographs or maps that will be included with the plan. 5 5) Conclusion and proposed solution(s).The Comprehensive Flood Control Management Plan must befinalized by the following action from the appropriate local authority: (a) Evaluation of problems and needs; (b) Evaluation of alternative solutions; (c) Recommended corrective action with proposed impact resolution measures for resource losses;and (d) Corrective action priority. The April 2021 Draft Comprehensive Planning for Flood Hazard Management:A Guidebook outlines the following steps: Step 1: Identify Related Regulatory Programs and Planning Priorities Step 2: Establish Process for Public and Agency Participation Step 3: Draft Short-and Long-term Goals and Objectives for Flood Hazard Management Step 4: Inventory and Analysis of Physical Conditions and Other Technical Issues Step 5: Set Short-and Long-term Goals and Objectives for Flood Hazard Management Step 6: Determine Need for Flood Hazard Management Strategies and Measures Step 7: Identify Alternative Strategies and Measures for Flood Hazard Management Step 8: Evaluate Alternative Strategies and Measures Step 9: Hold Public Alternative Evaluation Workshop(s) Step 10: Develop Strategy and Implementation Approaches for Flood Hazard Management Step 11: Complete Draft CFHMP and SEPA Documentation Step 12: Submit Final CFHMP to Department of Ecology Step 13: Hold Public Hearing and Adopt the CFHMP 6 APPENDIX C Public Outreach Survey Results and Summaries 1.0 PUBLIC OUTREACH SUMMARY 1.1 Public Outreach Activities Public outreach was an integral part of this project. However,the project was challenged by the COVID- 19 pandemic and the "Stay Home, Stay Healthy" order which went into effect just before the first planned outreach event.The Planning Team was forced to pivot and develop an online-only outreach plan that met the intent of the CRS program while reaching the widest audience possible. Throughout the planning process,the Planning Team utilized several methods of outreach to provide interested members of the public information about the project and opportunities to participate.These methods and opportunities are described below: Figure 1. Press Release. 1.1.1 Stakeholder Meeting Press Release The FCZD prepared a press (be!WA Ricer Basin Hoor!(intro!Zone!)Is/riet 14 111 No,N Sr release (Figure 1)to notify 1.AP114„.,.r1..rtitn,,,Wow....«, e,e....» ++,u.,u,•, interested members of the public that the planning CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT process was beginning,to COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN UPDATE direct them to the project The Chehalis River Basin Flood Control Zone District(FCZD)is currently updating website, and to invite the the Lewis County Comprehensive Flood Hazard Management Plan(CFHMP).The ublic to attend update Is being led by Betsy DIM from Lewis County Public Works and guided by P a group of Stakeholders comprised of representatives from Lewis County,the stakeholder meetings. cities of Chehalis and Centralia,Department of Ecology,FCZD Advisory Committee,and the public A CFHMP provides an overall strategy of programs.projects.and measures aimed at reducing the adverse impacts of flood hazards on the community The plan will coordinate and support the activities occurring within the Chehalis River Basin and provide guidance for FCZD projects and activities within Lewis County The project is funded by a grant from the Chehalis River Basin Flood Authority and will be completed by June 30,2021 Information about the project including Stakeholder meeting dates,agendas.and summaries will be posted on the FCZD website. htu29;(/wwyy:chehal snverbasinftiz4.c4m/cfhmp.Stakeholder meetings are open to the public,The next Stakeholder meeting will be at 10.00 a m.Tuesday,March 24, and will be held online Future meetings are planned to be held in the Lewis County Public Services building large conference room at 2025 NE Kresky Ave In Chehalis For questions,please contact Betsy Dillin at 360-740-1138 DATED this 201h day of March,2020 Lara McRea,Interim Clerk of the Board Notice sent to media March 20,2020 1.1.2 Project Website The Planning Team developed a project website that provided a link to all outreach materials,the current plan, and meeting agenda and minutes (Figure 2).The website was updated throughout the planning process to add meeting agendas and meeting summaries, and when the draft plan was released in August 2021 (Figure 3). Figure 2. Project Website(March 2020). CHEHALIS RIVER BASIN FLOOD HOME ASCU' NEWS QUICK LINKS EIS AND SUPPORTING DOCUMENTS CONTACT CONTROL ZONE DISTRICT Comprehensive Flood Hazard Management Plan Update (CFHMP) A CFHMP provides an overall strategy of programs,projects,and measures aimed at reducing the adverse impacts of flood hazards on the community.The plan will coordinate and support the activities of the Office of the Chehalis Basin.and provide guidance for FCZ1) projects and activities within Lewis County, Previous CFHMP-2009 Lewis County Comprehensive Flood Hazard Management Plan Meeting data,Agendas,Meeting Minutes Interactive Plan Website f Figure 3. Project Website (August 2021). CHEHALIS RIVER BASIN FLOOD HOME ABOUT NEWS QUICK LINKS E'S AND SUPPORTING DOCUMENTS CONTACT CONTROL ZONE DISTRICT Comprehensive Flood Hazard Management Plan Update (CFHMP) Save the Date CFHMP Open House- Wednesday,September 1,2021 Press release CFHMP INTERACTIVE PUN WEBSITE Chehalis River Basin Comprehensive Hood Heard Management Plan-DRAFT CFHMP Appendices-DRAFT Display Maps Action Table Figure 4. FCZD Email. 1.1.3 Online Open House Public Notification Item. tam McKee"Len hicaeareMw+sro,rntywe dove reared an email Sublet,, CoMW.Aad 10 enFlo01421AM The FCZD prepared � mp.Mnwe Feed NrreM M.nagnrtrM Pan tlldn!e release to be sent to over 800 members of the public and the press.The notification invited the public to attend the online open house,take the survey, and participate in the interactive web (t,,a.,,,0 ,,,,,o,r,ddpO ,e4t.yp„tr,.y map (Figure 4).The email was CHEHAUS RIVER BASIN also sent out by the Chehalis SIL 0$A7"°°"""'Ili`"`"t"'''""0$I Basin Flood Authority to a mailing i y list of over 100 interested ` ` ', 1.-;~ members of the public (Figure 5). `- zrr' e THE CHEHAUS RIVER BASIN FLOOD CONTROL ZONE DISTRICT 13 UPDATING THEIR COMPREHENSIVE FLOOD PLAN Inn C..Wuxnlw Rim.Bali"Pod Control Zoo.Meerut IF nin1 R+r wrM,tly uo�lnhrw the Lawn County Cpnpah.nsi.F►nod Hatatd hlwteotonibo Fran jCFMfi't Thu updae is bang bed by Betty U+Mn 170m Low*County Pudic Worts and undid by e VW()N Ste►aholdo s carywhar M nrpesantpMwn from l.wn County Ihe r bog of Chisholm argil Cn*d y Qepdbrgie4 td Ftcaogy Fd;7D Adv rry Cte.nutten attl by pub," A CFHI.w Poor",en overall Otology of program'projects,and measure'aimed al maucnp are adverse impacts of flood naiardl on the co vnundy The plan wall cooMnam and support the acvvloas octvmrsg*Tut Si.Cnehulrs Rh",Basin end cods yultlumn ha FCZD pints end ateatns wit!wt lawns COW 4y The roost'Is forced by a pant Wont the Chosh&+e Rls.r Barn Flood Aulhorly and MI be completed by June 30.Z021 A SLory step has bow,deceived to seep you intotnyd tte AAFIck l the pa:.o* and woods you en ooporunly b perk-vete online in bed of a Dude.m.otng dunrp tell'Stay Horne Stay Ha abh%Cede, Ti'.labs across the by or the"robbers"Mod,yap mWnnatnn end c0porursty a tsennwr*Wpm*"feel eel Peas.take or survey trot show In rem of content on out Iner.cbwe mop Dunn;the plannng process you*0 be owned to attend pubes meetings and".,new the Wen fen M..►np delis rub Si uttwbs.d end pooled wen My ere detvunmed CRIMP wabsle adds..,. For dusebons pleas.contact Betsy Dan et 3a0 740 1130 Our mailing address is. 351 NW North SI Chehana.WA 0E532 360 740 113E Figure 5.Chehalis River Basin Flood Authority Email. From: Pat Anderson<Pat.Anderson@lewiscountywa.gov> Sent: Monday,May 4,2020 11:12 AM To: Pat Anderson Subject: Comprehensive Flood Hazard Management Plan Update Attachments: Comprehensive Flood Hazard Management Plan Update Greetings The Chehalis River Basin Flood Control Zone District is updating the Lewis County Comprehensive Flood Hazard Management Plan. If you live or work in Lewis County the Flood Control Zone District needs to hear from you. Please take a few minutes to complete the following short survey https://www surveymonkev com/r/ORYBLPH. Your input is very important. You can also learn more about the Comprehensive Flood Hazard Management Plan Update at https:l/arcg.ishKW8vS,or by viewing the attached email,or contacting Betsy Dillin at 36o-740- 3.138 or Betsy.Dillinalewiscountywa.gov. Thank you for your assistance! Scott Boettcher,Staff Chehalis River Basin Flood Authority 360/48o-6600 scottb(hsbgh-partners.com 1.1.4 Online Open House project team developed the story map to provide information to the public about the project. The story map included information about the project, a timeline of flooding history in the river basin, survey, and a link to an interactive map meant to gather comments from the public.The story map was left active and members of the public could view it at any time throughout the planning process. It was viewed over 1,200 times between April 2020 and August 2021. Complete story map pages are provided in Section 2.0 of this appendix. 1.1.5 Survey The Planning Team developed a survey to gather input from the public.Thirty-five members of the public responded to the survey. Full survey results are provided in Section 3.0 of this appendix. 1.1.6 Social Pinpoint Map Social Pinpoint is an online engagement tool that allows members of the public to place a pin with comments on a map (Figure 6). Other users can view the comments and like or dislike to comments.This activity was not successful in gathering public input, which may be attributed to the COVID-19 pandemic overshadowing the planning process. Figure 6. Social Pinpoint Map. > 0 0 0 4 Q T • , 't,:er...***3•Ipt ... -‘ '" . - • Nit- tom, � _+4, 1I- �� .R ."�.RCn.nars►A Y "'• �� , 11 ell 11 s t ' , , •• ..• .., 'it` h ', �.`*^n j .,- —7.A i �'Ji?%.. {y_ ! ° I t w '1 ' 7 T4 4 L X Y. t... cut. tat '*G Goole .. ......�_ - 1.1.7 Draft Plan Press Release and Notice of Open House The Planning Team prepared a press release to notify the public and press that the draft plan was completed and ready for review, and that a hybrid open house was scheduled (Figure 7).The press release was sent to the press and to over 1200 people who had subscribed to receive county news updates (Figure 8).The local newspaper,The Chronicle, published the notice a week prior to the open house (Figure 9).The comment period for the draft plan review was open from August 24, 2021, to September 30, 2021. Only one comment was received. During this time,the Planning Team also sent the draft to CRS for a curtesy plan review. Figure 7. Draft Plan Press Release. Chehalis River Basin Flood Control Zone District Ertl P. lianas.P.L.. llt,ttt,! Limit,Arran,' NOTICE OF OPEN HOUSE CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT NOTICE is hereby given that the Chehalis River Basin Flood Control Zone Distract Supervisors will host an open house for the public to learn more about the draft Chehalis River Basin Comprehensive Flood Hazard Management Plan.This open house will be both in-person and online using Zoom. WHEN: Wednesday, September 1, 2021 TIME: 5:30 p.m.—6:30 p.m. WHERE: Lewis County Commissioners Hearing Room,second floor 351 N.W. North Street, Chehalis WA 98532 The Comprehensive Flood Hazard Management Plan(CFHMP)is focused on the portion of Lewis County within the Chehalis River Basin The goal of the plan is to minimize the long- term risk to life and property from flooding, The CFHMP evaluates the nsk and vulnerability to flooding and identifies mitigation actions the community can take to reduce the impacts of flooding It also includes goals,objectives,and policies to support the local agencies when making decisions related to flooding. For the past two years. a stakeholder committee of local officials and citizens have been meeting to develop the plan The committee is ready to present to the plan to the public for review and comment. The public comment penod ends on September 30, 2021. During the open house, the project team will provide an overview of the planning process, the results of the risk assessment. and the proposed mitigation actions. If you are unable to attend the open house, you can visit our interactive website to learn more about the plan and provide comments You can download the plan and find out more information at: https./iwww.chehalisnverbasinfczd.comicfhmp. Please submit comments on the draft CFHMP by September 30. 2021 using the comment form on the project website or by emailing the Project Manager,Betsy Dillin, Contact Betsy for more information at 360-740-1138 or by emailing Betsy.Dillinc lewiscountywa.gov. DATED this 24th day of August 2021 Lara McRea, Interim erk of the Board Notice sent to media. August 24, 2021 Figure 8. County Email. From:BOCC<BOCC@Iewiscountvwa,Rov> Sent:Tuesday,August 24,2021 2:56 PM To:Lara McRea<Lara.McRea@lewiscountvwa.Rov> Subject:Notice of Open for House Chehalis River Basin Flood Control Zone District Chehalis River Basin 2 Flood Control Zone District NOTICE OF OPEN HOUSE CHEHALIS RIVER BASIN FLOOD CONTROL ZONE DISTRICT NOTICE is hereby given that the Chehalis River Basin Flood Control Zone District Supervisors will host an open house for the public to learn more about the draft Chehalis River Basin Comprehensive Flood Hazard Management Plan.This open house will be both in-person and online using Zoom. WHEN: Wednesday,September 1,2021 TIME: 5:30 p.m.—6:30 p.m. WHERE: Lewis County Commissioners Hearing Room,second floor 351 N.W.North Street,Chehalis WA 98532 The Comprehensive Flood Hazard Management Plan(CFHMP)is focused on the portion of Lewis County within the Chehalis River Basin.The goal of the plan is to minimize the long- term risk to life and property from flooding.The CFHMP evaluates the risk and vulnerability to flooding and identifies mitigation actions the community can take to reduce the impacts of flooding.It also includes goals,objectives,and policies to support the local agencies when making decisions related to flooding. For the past two years,a stakeholder committee of local officials and citizens have been meeting to develop the plan.The committee is ready to present to the plan to the public for review and comment.The public comment period ends on September 30,2021. During the open house,the project team will provide an overview of the planning process,the results of the risk assessment,and the proposed mitigation actions.If you are unable to attend the open house,you can visit our interactive website to learn more about the plan and provide comments.You can download the plan and find out more information at: httos://www.chehalisriverbasinfczd.cornicfhmo. Please submit comments on the draft CFHMP by September 30,2021 using the comment form on the project website or by emailing the Project Manager,Betsy Dillin.Contact Betsy for more information at 360-740-1138 or by emailing Betsv.DillinCc ilewiscountywa.00v. DATED this 24th day of August 2021. Lara McRea,Interim Clerk of the Board Notice sent to media: August 24,2021 Figure 9. News release on open house. Flood Hazard Management Plan then House Next Wednesday ,..:',t ...- **S!'. .. -,.. -------A ,, a ,. .. ..... ,,- ., . ,...-,--'' ,........... - ........„ ., , ....„ .'r-rTil_.: .1.--T-1.1',.. .....----- ,..,,, If, . 1 .,; .4.:. ll .fif ' I ii imswkt f i , it _ ,e Cce;ntt rourtt?ausf By The Chronicle staff The public can learn more about the Chehalis River Basin Comprehensive Flood Hazard Management Plan next Wednesday at 5:30 p.m at an open house event The plan is focused on land in Leans County within the Chehalis River Basin and aims to minimize long-term flood risks to life and property. "For the past two years,a stakeholder committee of local officials and citizens have been meeting to develop the plan 1 The committee is ready to present the plan to the public fot review and comment,"read a news release 1 During the event,the project team will present on the planning process,the results of risk assessments and proposed nutigation actions Comments on the plan can be submitted through Sept 30 by going online to chehahsnverbasmfczd corn cfhmp,or by emarling project manager Betsy Dillin at Betsy Dillinilewiscountvwa gov The event will be held at the hearing room in the historic courthouse in Chehalis I 1.1.8 Online Open House Update Prior to notifying the public of the draft plan,the Planning Team updated the online open house story map.The update described the plan, invited the public to provide comment, and summarized some of the actions.The full pages for the story map are in Section 2.0 of this appendix. 1.1.9 Hybrid Open House On September 1, 2021,the Planning Team hosted a hybrid style open house.Attendees were able to participate either in-person or on Zoom.A total of 15 people attended the open house (Figure 10). During the open house, the Planning Team gave a brief presentation about the planning process and the plan, and then had a discussion with the meeting participants. At the in-person open house, participants could view large display maps with the effective 100-year floodplain, modeled 100-year floodplain, and climate change 100-year floodplain.The Planning Team also provided a download link to Zoom participants to view the same maps.The Planning Team also prepared a map station where participants could provide their address and be given a map with a close up of their property compared to the three 100-year floodplains (Figure 11).The complete presentation and display maps are available in Section 4.0 of this appendix.After the open house,the local newspaper,The Chronicle, wrote an article about the presentation (Figure 12). Figure 10.Open House Sign-In Sheet. 1 MA it it rl li 2016023S 002 -Chehaks River Comprehent ve Flood Hazard Management Plan Update Open House-Sen In Sheet � September 1.2021 Tt2K i-111/1..d Erik Marti vl Attendees on Zoom — Chrtssy Bailey Cob Arrrr'+e,Lewis Consenanon O+strrct (arum Coates Rep Jaime 44etrera peot et Off — C.ndy Browse Con Avenil Winder ,- Kyle MacDonald Scott Boettcher(Chehalis River Basin Flood Authoe ty) The Chronicle 714 PERTEET Page 2 Figure 11. Map Station Example. Lewis County Courthouse / xMf ry r. '/7 . // 21'1 '.. ' " 'Ai*Ili f",/ /4‘" , 4 //', ...,.' ' . ,.• , , v/ ' ,/- 2 , , ,„ ,, /0,/,,,,,,,, , , ,, , , -,,,,,,- // 7 ,.. 4-,,, ' / r ,,%%; Ar ,fir / / / // " //, / / 411.**.: ,- / 1/ „1/,7,"///// j/I, ;:/ g.//A.;"i';Adk.k.:;‘i:,t ' / ;' /5175////r/, , /�' ,//// 4/ // ////// / ////i�j�, // -/ i . / //V 1, / / // , ,141 / s 1Ot25/2O21,11 26:58 AM 1.4E 1= ;i ,i3 005 ..t" World Tramspertator Lewis County Bo,nary I t t ► } t r r I { 1 ParCMs Effective t(N:•Year F txx7Ciam IFEAAA) O 004 ? +r CM Cites Mi.Modered 100-Year Ficoapia+n —Piarrtava Atea Watettoraes Modde+e4 100•Year C rmate Cnange Fwodpian ter •Kqr P','Mara u...x r,,.w:ac u. .v.,w^,y..,•:,k.rr{Wnr,n c.,..tr n wn�^u,4$4.44*r>...M+x nr aw...w,. r Figure 12. News article on open house. Climate Change Could Increase Local Flood Damage by Si Billion, According to New Plan Projections: Public Can View, Comment Now • lig "- 'ram to m... } . fi' f". • '11.7 / tor ° r 4.41 Receding floodwaters reveal acres of mud covering the small rural come .,n,ty of Curtis.Wash on Tuesday Dec 4 2007 mom SALSSLRY Poised Fndas.Sipestaber 3,2021 4 13 p. By Claudia Yaw I cyaw@chronline.com In 60 years,climate change could double the amount of property damaged in Lewis County by a 100-year flood, putting nearly 1,400 more structures res at risk That's according to modeling in the new Chehalis RAN et Basin Comprehensi'e Flood Hazard Management Plan, which the public can now vtew and comment on Presenting to the public this week.consultant Christina Wollman noted that about S2 2 billion of property— including 2.510 structures—is exposed in the floodplam based on the 100-year modeling,with S336 million highly vulnerable to damage In a model taking into account climate change about 60 years out that increases to 3.900 structures,S3 2 billion of exposed property and about S669 million of highly-vulnerable property This increased the exposure value by a billion dollars So that's just how much larger it gets how much more flood water there is Wollman said A mid-range estimate suggests climate change could increase flooding in Lewis County—caused by atmospheric ri ers from the Pacific—by 26°s m the next 60 years,although the high-end estimate is at 50°o. 1.1.10 SEPA Determination and Notification On September 20, 2021, Lewis County Community Development issued a SEPA determination of non- significance (Figure 13).The determination had a 14-day comment period, was posted on the SEPA Register, advertised in the local paper, and sent to agencies with jurisdiction. No comments were received. Figure 13. SEPA DNS. LEWIS COUNTY —STATE ENVIRONMENTAL POLICY ACT THRESHOLD DETERMINATION DETERMINATION OF NONSIGNIFICANCE (DNS) LEAD AGENCY: Lewis County-Community Development Department PROPONENT: Chehalis River Basin Flood Control Zone District(Betsy Dillin,PE) FILE NUMBERS: SEP21-0030 DESCRIPTION OF PROPOSAL: This is a non-project action to adopt the 2021 Comprehensive Flood Hazard Management Plan(CFHMP)within the Chehalis River Basin Flood Control Zone District (FCZD) within Lewis County. The CFHMP provides an overall strategy of programs, projects, and measures aimed at reducing the adverse impacts of flood hazards on the community.The plan will coordinate and support the activities of the Office of the Chehalis Basin, and provide guidance for FCZD projects and activities within Lewis County. LOCATION OF PROPOSAL: This is a non-project action and affects areas of Lewis County within the Chehalis River Basin Flood Control Zone District. THRESHOLD DETERMINATION: The lead agency for this proposal has determined that it does not have a probable,significant adverse impact on the environment. An environmental impact statement(EIS)is NOT required under RCW 43.21C.030(2)(c).This decision was made after review by Lewis County of a completed environmental checklist and other information on file with this agency and such information is adopted herein by reference.This information is available for public review at the following website: httPS://www.chehalisriverhasinfczd.com/cfhmp This DNS is issued under WAC 197-11-340(2); the lead agency will not act on this proposal for 14 days from the issue date below.Written comments may be submitted during the 14-day period. Responsible Official: Lee Napier,Director Lewis County Community Development 2025 NE Kresky Avenue Chehalis,Washington 98532 Contact Person: Karen Witherspoon,AICP,Senior Project Planner 2YPr? Wchterip0Vr: for Responsible Official Date of Issue: September 30, 2021 This SEPA determination may be appealed in writing to the Lewis County Hearings Examiner until 4 pm on October 21,2021 at the Lewis County Community Development Permit Center.Appellants should be prepared to make specific factual objections. The appeal procedure is established in Lewis County Code(LCC)Section I Z 110.130 and LCC Section 2.25.130. The administrative appeal fee is established by Resolution No.20-420 of the Board of County Commissioners. 1.1.11 Public Hearing On November 30, 2021,the Lewis County Board of County Commissioners and Chehalis River Basin Flood Control Zone District Board of Supervisors held a joint meeting to hold a public hearing prior to plan adoption.The County advertised the public hearing on November 18 and 25, 2021 (Figure 14). Figure 14. Notice of Public Hearing and Adoption. [ADD PUBLIC HEARING NOTICE TO FINAL] 2.0 STORY MAP PAGES Chehalis River Basin Chehalis River Basin Hood Control"Lane CNwin Chehalis River Basin Comprehensive Flood Hazard Management Plan :: , _ , Chehalis River Basin Flood Control Zone District ,� k a.....).11111.111.11"1".°1- --•40e ‘ c � -...--,...-A . f , , , ,, ' /- , 24 . The Draft Chehalis River Basin Comprehensive Flood Hazard Management Plan (CFHMP) is ready for public review! Click here for the draft plan! For the past year, Stakeholders within Lewis County have been meeting to update the CFHMP. Check out the "Planning Process" and "Project Background" tab to learn more about the process and the planning area within Lewis County. Attend our Open Hou • When: Wednesday, September 1st • Time: 5:30 - 6:30 pm • Where: Commissioners Hearing Room. The meeting will be both in-person and online using Zoom. Find the link to the Zoom meeting on the FCZD website. Keep scrolling to learn more about the plan, and be sure to leave us comments using the comment form or by emailing the County Project Manager, Betsy Dillin. For more information about the project, contact Betsy Dillin at 360-740-1138 or at Betsy.Dillin@lewiscountywa.gov. �• ... ,' 4 414 I 0 .1.0. A e -. , • % 404/4 i 47( :.P- - . X .., A 01I '1,4:40.' ., I ,, .,. 4, 7 • 'a .,, ''...1 VI 4.4 ..04e ii . , „ ... .... Wo, 4 # e , . `" i'. I flit •. t t • ..fr 4 WI r • At, d'4' \ * , O*P 4'' 11 A S G +it ` J 1 1 efi J 4' . -.i i 1 N. dt. What is in the CFHMP? The CFHMP is assembled in three parts: 1. Planning Process and Project Background 2. Risk Assessment 3. Mitigation Strategy Each part is summarized below. Photo: Main Street interchange in Chehalis. February 1996. col .. as t L":1 'links Part 1 - Planning Process and Background Part 1 of the plan provides: • Specific details about the planning process, such as meeting agenda items, names of stakeholders, and public outreach. • Information about Lewis County, such as history, climate, geography, demographics, and economics. Photo: Chambers Way. January 1990. Earthstar Go- jraohtt ��r= ') C)A F.,A E Pcrt t Powered by Et, Part 2 - Risk Assessment Part 2 of the plan outlines the flood hazards present in the Chehalis River Basin within Lewis County, and evaluates the :ask, exposure, grid vulnerability of the County and the Cities of Chehalis, Centralia, and Napavine and the Town of Pe Ell. The risk assessment is based off the results of a Hazus analysis. Hazus is a program developed by FEMA that estimates damage from flooding based on flooding depth, assessor data, Census data, and building replacement values. For this plan, we developed Hazus analyses for four flood scenarios: • Effective 100-year floodplain (FEMA Flood Insurance Rate Maps, also knows as the "regulatory floodplain") • 100-year flood based on a new flood model (similar to flood limits of the 2007 flood) • 100-year flood based on a climate change scenario in 50 years (mid-range scenario) • 10-year flood based on a new flood model. // The term "100-year flood" means a flood that has a 1% chance of occurring every single year. // A "10-year flood" has a 10% chance of occurring each year. // The interactive map shows the limits of the 100-yr Effective Floodplain in blue, the 2007 actual floodplain boundary in red, and areas they overlap are in purple. If you're on a cell phone, click on the map to interact. Legend 100-yr Effective Floodplain (FEMA) December 2007 Flood Limits This data is also available on the Lewis County GIS Web Map. ft. may* �'�S_A 1t�� V. ..4" —40-2,„'. •� . A •.. 6 u d` r aHI I ' .�•v•w.{4. Pa....L yy Sr ill t r .. y ` V tr ' ^r. a , t , c ', aT r Risk (Chapter 6) The Chehalis River Basin within Lewis County has a long history of flooding. For a comprehensive list of floods, view this story on the Chronicle's website written by Julie McDonald and Edna Fund. From Native American Legends to 2007: A History of Flooding in the Chehalis River Basin The tab labeled "Interactive Timeline" also has a comprehensive list of floods. Most flooding in Lewis County is associated with heavy rainfall. These rainfall events are often due to atmospheric rivers which bring several inches of rainfall in a short time. The Pineapple Express is an atmospheric river that bring warm moist air from the tropics. s � 1 It_ _ M This image shows the atmospheric river that brought storms in January 2021. Photo: Chehalis. December 1933. r • NsB¢�t i�,�E. .-. s; ., - Ill' 4 _ ,4 .c'—wed' • r •r, ' •,. C. t `t K t 1.M.' .#.S_ _ ' - _J Rn'_J4 .G`. 'r4.. • .i.Z: 'V.i' . 1 �. , � 4 • s 4 . +em pty tea' ,If . = .0 yw. . Exposure (Chapter 7) Using the results of the Hazus analysis, we evaluated the number of structures within each of the floodplain scenarios to determine how many structures are exposed to flooding. We also estimated the value of the structures and contents within the floodplains. We found that in the Chehalis River Basin 100-year effective floodplain (FEMA), there are 2,260 structures within 30,210 acres of floodplain. This is 1.9 billion of exposed structures and content, or 15% of the total value of all structures and content within study area (2019). sing the modeled 100-year floodplain (similar to the 2007 flood), we found there to be 52.' billion in exposed Lt. ui. .u, c aiiu t.,u l �iiL_ , or 18% of the total value (2019). And using the climate change model, we found there to be $3.19 Billio,, 1„ Cnt)0.C Jt, Uiiu,aes and content, or 26% of the total value (2019). Photo: Chambers Way. December 2007. Most homeowners insurance does not cover flood damage. But with flood insurance you 're covered. FEMA Anrww c,,rxo Vulnerability (Chapter 8) Vulnerability assesses the people and structures that are at most risk. For example, a house that has been elevated may be exposed to flood risks, but it will have very little damage, so it has low vulnerability. People with disabilities are more vulnerable to flooding, because they may be unable to evacuate themselves and may require assistance. Landowners who do not have flood insurance are also more vulnerable to flooding, because homeowners insurance does not cover flood damage. They may be entirely responsible for the cost of repairs to their damaged structure. Our analysis found that property owners have bought enough flood insurance to cover only $432 million of the estimated $1.95 billion of structures and contents within the floodplain. For more information on flood insurance, visit Floodsmart.gov • 4 Part 3 - Mitigation Strategy Mitigation is the process of reducing exposure and vulnerability to flooding. Flood mitigation is either structural or non-structural. Structural flood mitigation often includes levees, floodgates, or other structures that control where floodwaters go. Non-structural flood mitigation often includes elevating structures, building farm pads for livestock, creating open space, or changing building codes. Click on the tab labeled "Mitigation Actions" to review the mitigation actions identified by the Stakeholder Committee. Photo: Farm pad for livestock. itilx ChehalisRiverBuin Planning Process i , , ,. , 1 -- , . . ..., • ,, .. , , - , 41 ' - f i 5 , ,. .., . . , . .3, 4 lr i sr_ ...„........ k� ter! on ta w Planning Process The planning team is following a 10-step planning process. Each step is described below. . : uns± s .s, . fat y t l � �,. � ! j� r t -a x �L.V N': ik'"?. , . ‘ if,,,,,- ' - - - v ..4•414 # 4111470 -10 ' :' -U. r _ fill:41 . ..'_...." S.J '.,..' '_..•-�.' ...._ ��. �.+..' .. .= a y eM r a - — g � -ter,;,,+• �► " likosivoismoismay. "0.4444, 46'9. qr.6- 1* . . 11 . -s 1r Step 1: Organize A stakeholder committee was formed to guide the planning process. The committee includes representatives from Lewis County, the cities of Centralia and Chehalis, Department of Ecology, and interested citizens. The committee generally meets on the 4th Tuesday of each month. For exact meeting dates and locations, agendas, and meeting summaries, visit the FCZD website. All stakeholder meetings are open to the public. Step 2: Involve the public Public participation is vital for the success of this project. There will be at least two public meetings during the process, the draft CFHMP will go through a public review and comment period, and the final plan will be adopted after holding a public hearing. Step 3: Coordinate The Chehalis basin has been studied for years by local, state, and federal agencies. Significant information already exists to help us understand risk, goals, and future plans for the basin. The planning team will review the existing information and coordinate with other agencies to ensure consistency at the local level. Much of the information we are reviewing is on the Chehalis Basin Strategy website. Step 4 and 5: Assess the hazard and the problem The planning team will identify the location and extent of flooding, using the best available and most current information, and assess how vulnerable the community is within the flood hazard area. This will include documenting past flooding and damages and assessing future flooding impacts which may result from development or climate change. The team will review the locations of critical facilities, such as fire stations, hospitals, and schools, and assess the economic value of infrastructure within the floodplain. Some of the information the planning team is using is already online. The Chehalis River Flood website shows where floodwater may reach during different flood stages. Step 6: Set goals The stakeholder committee will update the goals from the 2009 plan to identify priority actions and where mitigation should be focused. Step 7 and 8: Review possible activities and draft an action plan Once risk is fully understood and goals and policies are decided, the stakeholder committee will identify mitigation actions. These actions may be in support of larger, regional projects, or identify smaller projects that address local flooding or drainage issues. All possible activities will be evaluated for cost and feasibility. Activities that are determined to be cost-effective and feasible will be included in the action plan. An implementation plan will also be developed, which includes possible funding sources, which agency will lead the project, and which agencies can coordinate or support the project. Step 9: Adopt the plan Lewis County and the participating cities will adopt the plan after a public review and comment period. Step 10: Implement, Evaluate, and Revise The stakeholder committee will review the plan each year and discuss progress that has been made. The plan will go through an update process every five years. ChchalisRi.KrBU:::-in Project Background 41111 Hood t:omrol Gme `; - 't ice„ Y t i r 411P- Project Background Chehalis River Basin Comprehensive Flood Hazard Management Plan What is a CFHMP? A Comprehensive Flood Hazard Management Plan is a plan written by a local government to document goals and policies for the management of floodplains. The CFHMP will also identify actions that can be taken to reduce the impacts of flooding from the Chehalis River and its tributaries. The CFHMP will guide the Chehalis River Basin Flood Control Zone District (FCZD) administrators, Board of Supervisors, and Advisory Committee in FCZD operations. For more information about the FCZD, visit the FCZD website. Is this project related to the proposed flood retention facility or airport levee? Not directly. The flood retention facility is part of the Chehalis Basin Strategy. This CFHMP planning process is also part of the Chehalis Basin Strategy, but is focused on actions that can be taken by local government to address local flooding issues. More information about the flood retention facility can be found on the Chehalis Basin Strategy website. What is the study area? The CFHMP study area includes the entire Chehalis River Basin within Lewis County, including the cities of Centralia, Chehalis, and Napavine, and Town of Pe Ell. See map below. LaGrande • Centralia • e i National Geographic, Esri, Garmin, HERE,UNEP-WCMC. USGS, N... Powered by Esri Study area highlighted in red. Why is the plan being updated? The County's first CFHMP was written in 1994 and the most recent update was in 2009. The FCZD recently received a grant from the Office of the Chehalis Basin to update the plan. The plan is being updated to include new information, review and revise goals and objectives, and identify new mitigation projects and other actions. The current plan can be downloaded here. Who is updating the plan? The FCZD has hired a consultant to lead the planning process and write the plan. A stakeholder committee is guiding the planning process. The stakeholder committee includes representatives from the county, cities, state, and members of the public. ChehalisRierBuin Proposed Mitigation Actions Flcai c anard L.me!>Ix[rict . ._ t � Pe Ell on Rain ' - - • •te' • • r Pro d •Mitigation ose p Actions Chehalis River Basin Comprehensive Flood Hazard Management Plan During the planning process, the stakeholder committee identified several actions to include in the plan that will mitigate the flooding risk. These actions are focused at the county and city level, to reduce the impacts of local flooding. Some actions are existing programs that will remain on-going, other actions are long-term plans if and when funding becomes available. There are six categories of mitigation actions: • Preventativt actions keep flood problems from getting worse. • Structural prole' actions keep flood waters out of certain areas. • emergency service actions are taken during an emergency to minimize its impact. • Property protectiot actions are implemented by property owners. • Public information actions advise property owners, residents, and visitors about the hazard. • Natural resource protection actions preserve or restore natural areas or the natural functions of flood plains. Keep scrolling or click on the shortcuts on the top of this webpage to learn about some of the mitigation actions proposed in this plan. To review all mitigation actions, review Chapter 12 of the draft CFHMP. t..mibmhihira_t,.i.yti74,,.:.,...qio4...h.,, ...?...44is4_:-_ -.-.---•4isr- • ..:4:,1' - ,,_.,oh,t Ai.41Aptrigyi ,.,, .A....„.,.. .„ -- .t K .4-,,,,-,-c.4 . , L • ...00::"1 4%444:4 .stift qv._ ti:_w_1/4:4 :4 Prevention Actions • Action #8 - All participating agencies will continue to maximize federal, state, and local funding opportunities through grant application submittals in support of capital improvement projects, technical studies, and other flood hazard management activities. • Action #10 - All participating agencies will continue to maintain a database of flood control needs within the planning area as needs become identified for incorporation into future updates and progress reporting to this plan. • Action #11 - All participating agencies will continue to collect high water marks, recorded damages, photos, observed flood conditions, etc. • Action #14 —Lewis County and the Cities of Centralia and Chehalis will continue participating in the Community Rating System (CRS) process. • Action #17 - The FCZD will continue to participate and coordinate with the Office of the Chehalis Basin, the Chehalis River Basin Flood Authority, and other pertinent Chehalis Basin organizations to ensure projects and programs are consistent with larger basin- wide objectives. • Action #18 - All agencies will participate in updates to the County's Flood Insurance Rate Maps to ensure the maps accurately reflect local conditions. • Action #36 - The Cities and County will continue to maintain good standing under the National Flood Insurance Program by implementing programs that meet or exceed the minimum NFIP requirements. Such programs include enforcing an adopted flood damage prevention ordinance, participating in floodplain mapping updates, and providing public assistance and information on flood hazard requirements and impacts. • Action #40 - The FCZD will continue to utilize the best available data, science, and technology in their projects, programs, and outreach. Photo: SR 6 looking east towards Chehalis. December 2007. PItt- Overflow Spillway r Passage Tunnels i ✓• am''. 4 1 Spillway Fllp Bucket _ r �- f' M / _ } s ;Works Stilling Besin , .11,♦ ?' •f�4. \-.•:7 irl,:,),-.-sirl.--m ,-.. ' Structural Project Actions • Action #1 - The FCZD will continue participation and implementation of the flood damage reduction projects that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis Basin. • Currently the FCZD is working on the Flood Retention Facility and the Chehalis-Centralia Airport Levee projects. For more information on these projects, visit the Chehalis Basin Strategy website. • Action #3 - The FCZD and other agencies such as the City of Chehalis, Port of Chehalis, and Lewis County, will develop a Newaukum Unit Drainage Basin Plan for Dillenbaugh, Dilly, and Berwick Creeks. The plan will identify cost effective and feasible structural and non- structural actions that will minimize future peak flow increases. The study should include the area between Armstrong Road and Jackson Highway adjacent to Logan Hill Road. • Action # 4 - The FCZD will identify sources of local funding to fund FCZD administration and leverage alternative funding sources. • Action #9 - The Cities and County will mitigate flood related risk to publicly owned County and City bridges. • Action #24 - The FCZD and Public Works will continue to support projects that evaluate the feasibility of regional stormwater detention facilities to address increased stormwater runoff for development in the basins that occurred prior to implementation of site- specific stormwater management measures. • Action #26 - All jurisdiction that participated in the CFHMP planning process will continue to participate in developing flood control projects with other entities such as the Chehalis River Basin Flood Authority, Office of the Chehalis Basin, USACE, and the Washington State Department of Transportation (WSDOT). Image: Proposed Flood Control Facility. 1 0 F° t" Emergency Services Actions • Action #22 - The FCZD will continue to maintain their website to provide Chehalis River Basin information and links to the flood warning system and all other related websites and information. • Action #28 - All participating jurisdictions will continue to support projects that would mitigate or relocate utilities and critical facilities which are subject to flooding. • Action #29 - Lewis County Emergency Management will continue to encourage NIMS/ICS training for staff that may work within or interact with the Emergency Operations Center (EOC). • Action #30 - Lewis County Emergency Management and other county agencies will work together to develop flood response plans to include response and recovery roles, responsibilities, and priorities, flood early warning system procedures, pre-identified detour routes, criteria to assist emergency response personnel in determining what actions are appropriate when providing assistance to private property during the response and recovery phases, and a list of not-for- profit essential service providers that provide community support during and after a flood event. • Action #37 - Lewis County Emergency Management will work with the Cities and County to develop a communication protocol plan and provide training to all County and city responders on new protocol and system upgrades as funding becomes available. • Action #38 - Lewis County Emergency Management and the Public Works Department will map detour routes and share routes with WSDOT to assist in efficient detour planning. mil ✓ y. • ia —tt: r .. • aiyh p� Phi • Public Education and Awareness Actions • Action #15 - The Cities, County, and Emergency Management will continue to deploy public information and outreach program targeting at-risk properties within the planning area. • Action #19 - The County will continue to maintain on online web map with information layers such as CMZs, dam and levee breach inundation areas, and critical areas. • Action #2:: - The County and Cities will continue to provide outreach and educational materials for the public on flood hazards, risks of development in floodplains, NFIP regulations, and flood mitigation programs, including annual mailings to flood prone properties and placing flood information at local libraries. • Action #39 - All participating agencies will support updates to the flood warning system to ensure it utilizes the best available data, science, and technology. Photo: SR 6 landslide near Pe Ell. December 2007. ' ', '''wt 7 i I 4 i . , 4 „,t i i _ 4... 44 x' • ti asy-alr,» k : i � te t r + y- Property Protection Actions • Action #2 - The FCZD will develop a technical assistance program to support landowners with bank stabilization and/or post-disaster debris removal. • Action #7 - When requested, FCZD may act as the applicant agent for mitigation grant opportunities for private property requesting to participate in the grant program. ii. .fie k �,•.-1.11k.1. ' II* '''-'71111:1411111.114.111411111t. WO" ::•.°" ‘ I .' , '01k...1141111‘4.**7.. 10"1.14:21‘.. 211111131' ' ' arill ob .,. ., ems ...,,` J .... ♦ Natural Resource Protection Actions Many of the proposed actions include a natural resource protection component. One action with a great focus on natural resource protection is: • Action #1 - The FCZD will continue participation and implementation of the flood damage reduction projects that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis Basin. The Chehalis Basin Strategy includes a plan for aquatic species restoration throughout the entire Chehalis River Basin. The plan is described in more detail in the draft Aquatic Species Restoration Plan, which can be viewed on the Chehalis Basin Strategy website. 3.0 SURVEY RESULTS Chehalis River Basin Comprehensive Flood Hazard Management Plan Q1 Where in Lewis County do you live? Answered: 35 Skipped: 0 Chehalis Centralia Pe Ell Napavine Unincorporate Lewis County. Outside of th. Chehalis Riv. I do not live in Lewis County Other(pleas: specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Chehalis 17.14% 6 Centralia 0.00% 0 Pe Ell 0.00% 0 Napavine 0.00% 0 Unincorporated Lewis County within Chehalis River Basin 48.57% 17 Outside of the Chehalis River Basin, including: Cowlitz River Basin (Winlock, Toledo, Vader, Packwood, Morton, 11.43% 4 Mossyrock, etc), Deschutes River Basin, or Nisqually River Basin I do not live in Lewis County 11.43% 4 Other(please specify) 11.43% 4 TOTAL 35 1/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q2 Do you work in Lewis County? Answered: 35 Skipped: 0 Yes No 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 57.14% 20 No 42.86% 15 TOTAL 35 2/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q3 Do you live in a known floodplain or area that has been subject to flooding? Answered: 35 Skipped: 0 Yes No Not Sure 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 34.29% 12 No 57.14% 20 Not Sure 8.57% 3 TOTAL 35 3/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q4 Do you own or rent your place of residence? Answered: 35 Skipped: 0 Own Rent 0% 10% 20% 30% 40% 50% 60% 70% 8 0% 90% 100% ANSWER CHOICES RESPONSES Own 94.29% 33 Rent 5.71% 2 TOTAL 35 4/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q5 Do you have a mortgage? Answered: 35 Skipped: 0 Yes No 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 51.43% 18 No 48.57% 17 TOTAL 35 5/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q6 Is this your primary residence or is it your vacation/second home? Answered: 35 Skipped: 0 Primar residenc Vacation o second horn 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Primary residence 94.29% 33 Vacation or second home 5.71% 2 TOTAL 35 6/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q7 How prepared is your household to deal with a flood event? Answered. 35 Skipped: 0 17 (no label) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Not at All Prepared li Somewhat Prepared In Adequately Prepared al Well Prepared MI Very Well Prepared NOT AT ALL SOMEWHAT ADEQUATELY WELL VERY WELL TOTAL WEIGHTED PREPARED PREPARED PREPARED PREPARED PREPARED AVERAGE (no 5.71% 20.00% 28.57% 28.57% 17.14% label) 2 7 10 10 6 35 3.31 7 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q8 Which of the following have provided you with useful information to help you be prepared for a flood event? Answered: 35 Skipped: 0 Emergenc preparedness. Persona experience w.. Locall provided new.. Schools other academ.dem. A meetingsgs tha.tha. Community Emergency... Faith-base institution None Other(pleas specify. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Emergency preparedness information from a government source(e.g., federal, state, or local emergency management) 45.71% 16 Personal experience with flood events 62.86% 22 Locally provided news or other media information 54.29% 19 Schools and other academic institutions 14.29% 5 Attended meetings that have dealt with flood preparedness 31.43% 11 Community Emergency Response Training(CERT) 14.29% 5 Faith-based institutions 11.43% 4 None 8.57% 3 Other(please specify) 8.57% 3 Total Respondents: 35 8/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q9 Which of the following steps has your household taken to prepare for a flood event? (Check all that apply) Answered: 35 Skipped: 0 Identified utility... Sand bags. Stored flashlights ... Stored a I. battery-powe... Stored medical supplies(fi... Purchase= flood insuranc Prepared ,-- disaster sup. Identified a least 2 meth. Stored foo and water ab.. 11111111. Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 9/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan ANSWER CHOICES RESPONSES Identified utility shutoffs 71.43% 25 Sand bags 5.71% 2 Stored flashlights and batteries 85.71% 30 Stored a battery-powered radio 51.43% 18 Stored medical supplies (first aid kit, medications) 82.86% 29 Purchased flood insurance 14.29% 5 Prepared a disaster supply kit 51.43% 18 Identified at least 2 methods for receiving emergency notifications and information during emergencies 45.71% 16 Stored food and water above potential flood levels 85.71% 30 Other(please specify) 20.00% 7 Total Respondents: 35 10/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q10 How concerned are you about the following flood related hazards in Lewis County? (Check one response for each hazard) Answered: 34 Skipped: 1 Ice Jams Post-fire flooding Riverine flooding ■ >4: * . M River/Channel a migration �� s .,. �. . 11/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Stream bank erosion s y Urban flooding/Dra... Land subsidence Mudflow hazards 12 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Dam failure Climate change impact4 Other 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% II Not Concerned Somewhat Concerned ei Concerned 111 Very Concerned ■ Extremely Concerned 13/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan NOT SOMEWHAT CONCERNED VERY EXTREMELY TOTAL CONCERNED CONCERNED CONCERNED CONCERNED Ice Jams 73.33% 6.67% 13.33% 6.67% 0.00% 11 1 2 1 0 15 Post-fire flooding 30.00% 30.00% 20.00% 20.00% 0.00% 3 3 2 2 0 10 Riverine flooding 5.88% 29.41% 17.65% 29.41% 17.65% 1 5 3 5 3 17 River/Channel 25.000/0 8.33% 41.67% 16.67% 8.33% migration 3 1 5 2 1 12 Stream bank erosion 5.26% 31.58% 26.32% 26.32% 10.53% 1 6 5 5 2 19 Urban 23.53% 0.00% 35.29% 29.41% 11.76% flooding/Drainage 4 0 6 5 2 17 issues Land subsidence 30.77% 23.08% 38.46% 7.69% 0.00% 4 3 5 1 0 13 Mudflow hazards 27.78% 22.22% 33.33% 5.56% 11.11% 5 4 6 1 2 18 Dam failure 56.52% 4.35% 13.04% 13.04% 13.04% 13 1 3 3 3 23 Climate change 33.33% 19.05% 9.52% 19.05% 19.05% impacts 7 4 2 4 4 21 Other 25.00% 0.00% 12.50% 25.00% 37.50% 2 0 1 2 3 8 14/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q11 Choose five (5) of the following methods you think are most effective for providing flood hazard and disaster information? (Choose up to 5 answers) Answered: 35 Skipped: 0 Newspaper Telephone Book Information Brochures Local Government.. Public Meetingsillilli Workshops Schools TV News TV Ads Radio News Radio Ads Internetilill Outdoo 'a. Advertisement a` , Fir Department/R. Law Enforcement Faith-base Institution ution CERT Classes■ Public 15/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Awareness... Books Chamber of ■ Commerce Academic Institutions Public Library' Red Cros s! Informatio Communit Safety Event Fair Booths Word of Mouth Social Media (Twitter,... Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 16/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan ANSWER CHOICES RESPONSES Newspaper 37.14% 13 Telephone Book 0.00% 0 Information Brochures 17.14% 6 Local Government Newsletters 22.86% 8 Public Meetings 37.14% 13 Workshops 17.14% 6 Schools 25.71% 9 TV News 34.29% 12 TV Ads 11.43% 4 Radio News 62.86% 22 Radio Ads 22.86% 8 Internet 48.57% 17 Outdoor Advertisements 5.71% 2 Fire Department/Rescue 20.00% 7 Law Enforcement 14.29% 5 Faith-based Institutions 8.57% 3 CERT Classes 8.57% 3 Public Awareness Campaign (e.g., Flood Awareness Week, Winter Storm Preparedness Month) 28.57% 10 Books 0.00% 0 Chamber of Commerce 8.57% 3 Academic Institutions 0.00% 0 Public Library 2.86% 1 Red Cross Information 8.57% 3 Community Safety Events 14.29% 5 Fair Booths 17.14% 6 Word of Mouth 17.14% 6 Social Media(Twitter, Facebook, Instagram, etc.) 57.14% 20 Other(please specify) 2.86% 1 Total Respondents: 35 17 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q12 What method is best for you and your family to get time sensitive warning information or instructions for action? Answered: 35 Skipped: 0 Land-lin telephon Audible notification... Friends and family, Cell phone Text messagEIIIIIIIIIIIIIIIIII Email Radio TV Social networ (Twitter,.. Other(pleas specify. 0% 10% 20% 30% 400/0 50% 60% 70% 80% 90% 100% 18/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan ANSWER CHOICES RESPONSES Land-line telephone 22.86% 8 Audible notification (siren) 0.00% 0 Friends and family 2.86% 1 Cell phone 48.57% 17 Text message 60.00% 21 Email 25.71% 9 Radio 25.71% 9 TV 8.57% 3 Social network (Twitter, Facebook, Instagram, etc.) 25.71% 9 Other(please specify) 8.57% 3 Total Respondents: 35 19/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q13 Are you signed up to recive notifications from Lewis County Alert? Answered: 35 Skipped: 0 Yes No 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 68.57% 24 No 31.43% 11 TOTAL 35 20/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q14 What would drive you to action in response to an emergency notification? Answered: 35 Skipped: 0 Fear of injury or casualty Damage to personal... Potential' isolation Lack o� preparednes Perceived severity of... Other(plea specifyy. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Fear of injury or casualty 34.29% 12 Damage to personal property 42.86% 15 Potential isolation 11.43% 4 Lack of preparedness 2.86% 1 Perceived severity of the incident 65.71% 23 Other(please specify) 8.57% 3 Total Respondents: 35 21 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q15 Do you have flood insurance? Answered: 35 Skipped: 0 Yes No E Not Sure 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 11.43% 4 No 85.71% 30 Not Sure 2.86% 1 TOTAL 35 22 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q16 If you do NOT have flood insurance, what is the primary reason? Answered: 32 Skipped: 3 I don't nee it/my proper.. Don't nee it/located o. It is too , expensive ?` Not familiar with it/don'... Insurance company will... My existing homeowners... My existing renters... It is not worth it I have flooded before,so I... I believe it will affect... I have flood I insurance I don't know if I have fl... Other(please specify} 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 23/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan ANSWER CHOICES RESPONSES I don't need it/my property has never flooded 3.13% 1 Don't need it/located on high ground 62.50% 20 It is too expensive 15.63% 5 Not familiar with it/don't know about it 0.00% 0 Insurance company will not provide coverage 0.00% 0 My existing homeowners insurance provides coverage 0.00% 0 My existing renters insurance provides coverage 0.00% 0 It is not worth it 3.13% 1 I have flooded before, so I did not think I qualified for coverage 0.00% 0 I believe it will affect the value of my property 0.00% 0 I have flood insurance 3.13% 1 I don't know if I have flood insurance 3.13% 1 Other(please specify) 9.38% 3 TOTAL 32 24/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q17 How much money would you be willing to spend to retrofit your home to reduce risks associated with flood disasters? (e.g., elevating a home above flood level, flood-proofing, building berms or floodwalls) Answered: 33 Skipped: 2 Nothing Less than $1,000 $1,000 to!. $4,999 $5,000 to $9,999 $10,000 or !. above Not Sure Other(please specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Nothing 51.52% 17 Less than$1,000 9.09% 3 $1,000 to$4,999 12.12% 4 $5,000 to$9,999 0.00% 0 $10,000 or above 6.06% 2 Not Sure 18.18% 6 Other(please specify) 3.03% 1 TOTAL 33 25/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q18 Which of the following incentives would encourage you to spend money to retrofit your home to protect against flood disasters (Check all that apply) Answered: 34 Skipped: 1 Low interes rate home.. Grant fundin None Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Low interest rate home improvement plan 8.82% 3 Grant funding 55.88% 19 None 32.35% 11 Other(please specify) 14.71% 5 Total Respondents: 34 26/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q19 When you moved into your home, did you consider the impact of a potential flood could have on your home? Answered: 35 Skipped: 0 Yes No NM Not Sure Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 60.00% 21 Na 37.14% 13 Not Sure 0.00% 0 Other(please specify) 2.86% 1 TOTAL 35 27/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q20 Was the presence of a flood hazard disclosed to you by a real estate agent, seller, or landlord before you purchased or moved into your home? Answered: 34 Skipped: 1 Yes No Not Sure Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 14.71% 5 No 67.65% 23 Not Sure 14.71% 5 Other(please specify) 2.94% 1 TOTAL 34 28 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q21 Would the disclosure of the flood hazard have influenced your decision to buy or rent a home? Answered: 34 Skipped: 1 Yes No Not Sure Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 47.06% 16 No 38.24% 13 Not Sure 11.76% 4 Other(please specify) 2.94% 1 TOTAL 34 29/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q22 Do you support the preservation of natural land that contains a flood hazard? Answered: 33 Skipped: 2 Do suppor Do not suppor Other(please specify) 0% 10% 20% 30% 40% 50% 60%, 70% 80% 90% 100% ANSWER CHOICES RESPONSES Do support 66.67% 22 Do not support 27.27% 9 Other(please specify) 6.06% 2 TOTAL 33 30/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q23 Do you support the regulation (restriction) of land uses within known, high risk, flood hazard areas? Answered: 35 Skipped: 0 Yes No Not Sure Other(pleas specify 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 74.29% 26 No 11.43% 4 Not Sure 8.57% 3 Other(please specify) 5.71% 2 TOTAL 35 31/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q24 What types of projects do you believe the Local, State or Federal governemnt agencies should consider to reduce damage and disruption from flooding? Answered: 35 Skipped: 0 32 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Retrofi infrastructu. Capita projects suc. Strengths codes and.. Acquir vulnerable.. Assis vulnerable.. Provide bette information. 0% 10% 20% 3 0% 40% 50% 60% 70% 80% 90% 100% High II Medium r. Low 33/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan HIGH MEDIUM LOW TOTAL WEIGHTED AVERAGE Retrofit infrastructure, such as improving cultures, bridges, and local 43.75% 50.00% 6.25% drainage. 7 8 1 16 2.38 Capital projects such as dams, levees, flood walls and drainage 62.50% 16.67% 20.83% improvements. 15 4 5 24 2.42 Strengthn codes and regulations to include higher regulatory standards in 52.94% 23.53% 23.53% flood hazard areas. 9 4 4 17 2.29 Acquire vulnerable properties and maintain as open space. 44.44% 22.22% 33.33% 8 4 6 18 2.11 Assist vulnerable properties owners with securing funding for mitigation. 56.25% 31.25% 12.50% 9 5 2 16 2.44 Provide better information about flood risk to the public. 52.63% 31.58% 15.79% 10 6 3 19 2.37 34/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q25 If your property were located in a designated "high flood hazard" area or had recieved repetitive damages from flood events, would you consider a "buyout" offered by a public agency? Answered: 33 Skipped: 2 Yes No 1 Not Sure 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 63.64% 21 No 18.18% 6 Not Sure 18.18% 6 TOTAL 33 35/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q26 Please indicate how you feel about the following statement : It is the responsibility of government (local, state and federal) to provide education and programs that promote citizen actions that will reduce exposure to the risks associated with flood hazards. Answered: 35 Skipped: 0 I (no label) iii. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Strongly Disagree III Somewhat Disagree 111 Neither Agree nor Disagree Somewhat Agree • Strongly Agree STRONGLY SOMEWHAT NEITHER AGREE NOR SOMEWHAT STRONGLY TOTAL WEIGHTED DISAGREE DISAGREE DISAGREE AGREE AGREE AVERAGE (no 2.86% 5.71% 20.00% 48.57% 22.86% label) 1 2 7 17 8 35 3.83 36/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q27 Please indicate how you feel about the following statement : It is my responsibility to educate myself and take actions that will reduce my exposure to the risks associated with flood hazards. Answered: 35 Skipped: 0 (no label) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ▪ Strongly Disagree • Somewhat Disagree Neither Agree or Disagree • Somewhat Agree II Strongly Agree STRONGLY SOMEWHAT NEITHER AGREE OR SOMEWHAT STRONGLY TOTAL WEIGHTED DISAGREE DISAGREE DISAGREE AGREE AGREE AVERAGE (no 8.57% 2.86% 0.00% 25.71% 62.86% label) 3 1 0 9 22 35 4.31. 37/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q28 Please indicate how you feel about the following statement: Information about the risks associated with flood hazards is readily available and easy to locate. Answered: 35 Skipped: 0 3 'bt (no label) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Strongly Disagree MI Somewhat Disagree Neither Agree nor Disagree al Somewhat Agree Strongly Agree STRONGLY SOMEWHAT NEITHER AGREE NOR SOMEWHAT STRONGLY TOTAL WEIGHTED DISAGREE DISAGREE DISAGREE AGREE AGREE AVERAGE (no 8.57% 17.14% 17.14% 42.86% 14.29% label) 3 6 6 15 5 35 3.37 38/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q29 Are you aware of any local programs and policies designed to reduce risk from flood hazards? Answered: 34 Skipped: 1 Yes No 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 61.76% 21 No 38.24% 13 TOTAL 34 39/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q30 Do you have any special access or functional needs within your household that would require early warning or specialized response during disasters? Answered: 35 Skipped: 0 Yes No 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 11.43% 4 No 88.57% 31 TOTAL 35 40/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q31 Please indicate your age range: Answered: 35 Skipped: 0 Under 18 18-30 31-40 41-50 51-60 61 or older 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Under 18 0.00% 0 18-30 0.00% 0 31-40 2.86% 1 41-50 17.14% 6 51-60 20.00% 7 61 or older 60.00% 21 TOTAL 35 41/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q32 Please indicate your gender: Answered: 34 Skipped: 1 Male Female Other 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Male 73.53% 25 Female 26.47% 9 Other 0.00% 0 TOTAL 34 42 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q33 Please indicate your highest level of education Answered: 35 Skipped: 0 Grade school/ No schooling Some high school High school graduate/GED Some collegni College degre ',- Graduate degree or... Other(please specify) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 1 0 0% ANSWER CHOICES RESPONSES Grade school/ No schooling 0.00% 0 Some high school 0.00% 0 High school graduate/GED 0.00% 0 Some college 14.29% 5 College degree 45.71% 16 Graduate degree or higher 40.00% 14 Other(please specify) 0.00% 0 TOTAL 35 43/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q34 How long have you lived at your current residence? Answered: 35 Skipped: 0 Less than 1 year 1 to 5 years 6 to 10 years 11 to 20 years More than 2 '. years 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Less than 1 year 0.00% 0 1 to 5 years 17.14% 6 6 to 10 years 20.00% 7 11 to 20 years 22.86% 8 More than 20 years 40.00% 14 TOTAL 35 44/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q35 How much is your gross household income? Answered: 33 Skipped. 2 $20,000 or less $20,001 to $49,999 $50,000 toy $74,99 .!; $75,000 to $99 $99,99 $100,000 or more 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES $20,000 or less 0.000/0 0 $20,001 to$49,999 9.090/0 3 $50,000 to$74,999 18.18% 6 $75,000 to$99,999 30.30% 10 $100,000 or more 42.42% 14 TOTAL 33 45 /47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q36 Do you have regular access to the internet? Answered: 35 Skipped: 0 Yes No Not Sure 0% 10% 20% 3 0% 40% 50% 60% 70% 80% 90% 100% ANSWER CHOICES RESPONSES Yes 91.43% 32 No 8.57% 3 Not Sure 0.00% 0 TOTAL 35 46/47 Chehalis River Basin Comprehensive Flood Hazard Management Plan Q37 If you have additional information you would like to share about your knowledge and experience regarding local flood related hazards, we invite you to provide your information in the comment box below. Answered: 12 Skipped: 23 47/47 I/i./c.vL- t CHEHALIS RIVER BASIN COMPREHENSIVE FLOOD HAZARD MANAGEMENT PLAN ;It p E RTE E T CFHMP Open House Better communities,by design September 1, 2021 4:. ., -----, What is a CFHMP? iii l'\' Defines local goals and policies izi r Assesses the risk to people and property iiiIdentifies local mitigation actions to reduce risk 11 J/-L L J Why? The FCZD is required to have a plan. The previous plan is from 2009. The FCZD received a grant to prepare the plan. Having a plan supports funding requests. k. .t7A Planning Area f The portion of the Chehalis River Basin within Lewis County. h xt.+ e4uN Pork qty. 1 . a y Y I k� 'aJ�� -, �UM^C1ivM4.WrvsAM J/1/LVL 01 Planning Process Open House Agenda 03 Action Plan 04. Questions and Discussion 01 Planning Process Open House Agenda J�1�LVL 1i Planning Process Planning Team Members: • Betsy Dillin, PE, Public Works Project Manager, FCZD Project Manager • Erik Martin, PE, County Manager, FCZD Administrator • Lara McRea, Assistant to the County Manager, FCZD Clerk • Christina Wollman, Perteet— Project Manager/Lead Project Planner • Kirk Holmes, Perteet—Subject Matter Expert • Rob Flaner, Tetra Tech —CFHMP Expert • Carol Baumann, Tetra Tech — Risk Assessment Lead Planning Process Stakeholder Committee Members: • Lewis County Community Development, Public Works, and Emergency Management Departments • Chehalis Planning Department • FCZD Advisory Committee Members • Department of Ecology • Office of the Chehalis Basin • Citizen J/1/LUG Planning Process Consistency with other plans: • Reviewed plans, studies, data, and other information developed for the Chehalis Basin Strategy. • Used the same data to assess risk that is being used for the Flood Damage Reduction Projects. • Identified mitigation actions to address local issues that achieve the same goals as the Chehalis Basin Strategy. open 0 Risk Assessment House Agenda J�J/LVL Frequency & Severity - Historical Crests Per Year 5 4 3 A jj 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 -Chehalis at Centralia -Chehalis at Doty -Newaukum -Skookumchuck Risk Assessment Cause & History dig "'(' 't'" � A• J/1/LVL Risk Assessment Capabilities & Flood Warning System o a. _ o xi CHEHALIS elk PonMSummary }_Summary — ^. r,...i.... 106 LOji): River F:reCaa. f�uoC Maps Rbl Oape Gate itt, fiti 0 Risk Assessment HAzus EARTHQUAKE • WIND • FLOOD • TSUNAMI • Depth grids for flooding scenarios • Assessor data for building types, characteristics, and year of construction • Building replacement cost • Finished floor height analysis • Census data :I/i/we IIRisk Assessment I. ('Athas River ',•V`! _i r'i • • —• .AID. 100-Year Floodplain = N4 )�. ',.. _ft.' 1% Chance Floodplain fi -,-,r .4. ! - ` r y r' 'M IY Sarah F•rf I Pe MI ....4.,(I (.•.•(l,RL,r • 100-year effective floodplain j �r. �' -.,V f y (FEMA floodplain) 4... �/ A. -•.r.:' • 100-year modeled floodplain �; /�'f' , - 'PERTEET • 100-year climate change • • I 1 fe /%( -1 ouhe.,—..W, floodplain '- .Wit+ - �' r .--_ 11.110.0 Wean.II 'FEMN • 10-year modeled floodplain "' '• .r I " ' Risk Assessment ,, yogt 5 - 0 — 100-Year Climate Change "4'' Floodplain Z„:,r:,,: ....I._.t I NN - -• Cheh•Ii, • Year 2080 / , : , _ t � ,...(.•R( . • Map shows "Mid-Range" scenario As-',rim 11 �` ::: .sue,_ �,r>y '�/.y��-';f+,' 50%increase lid Eu •y,/ ,"4 .: 99� Oa .J/1/L V L Risk Assessment Exposure and Vulnerability I Structures and Contents Value 100-Year Modeled Floodplain Structures Value Exposed Value Vulnerable Total 2,510 $2,242,630,562 $336,310,766 100-Year Climate Change Floodplain Structures Value Exposed Value Vulnerable Total 3,900 $3,191,051,525 $668,955,909 Open House Agenda 03 Action Plan J/ L/L JL =IL Goals • Goal #1— Reduce and minimize flood related hazards to the public and emergency responders. • Goal #2— Reduce and minimize flood damage and _ , n •. financial impacts to the community. • Goal #3—Avoid impacts that cause flooding of downstream neighbors. • Goal #4—Avoid, minimize, or mitigate environmental impacts of flood hazard reduction activities. • • Goal #5— Increase public awareness and understanding of flooding. Action Plan Policies 4 • General _,r - Flood Hazard Management } ' • - Regional Consistency • Flood Hazard Area Land Use • Flood Risk Reduction • Funding and Financing • 1 .JI 1I LVL Action Plan Mitigation Actions Emergency Preparedness Cycle • 40 actions identified to reduce Prevention Protection risk to life and property Disaster • Mix of programs, studies, and projects Mitigation • Various lead agencies Response • Not all actions have funding Recovery Action Plan • Program — Action#14 —Lewis County and the Cities of Centralia and Chehalis will continue participating in the Community Rating System (CRS) process. — Action#36—Continue to maintain good standing under the National Flood Insurance Program by implementing programs that meet or exceed the minimum NFIP requirements. 1 .://i/we Action Plan • Studies Action#3—Develop a Newaukum Unit Drainage Basin Plan for Dillenbaugh, Dilly, and Berwick Creeks. • Projects Action#1—Continue participation and implementation of the flood damage reduction projects that are part of the Chehalis Basin Strategy sponsored by the Office of the Chehalis Basin. PAction Plan Flood Damage Reduction Projects Update i.4110100■00. ice-- • x .lr „a,tia•• i .1 ... o _ �• ..,. • , Almon Wm.Impromvierrts • irn. .. 4:uroen le.'ee worovemenn .711 Raised Rob Oisdna 1 J/11 LVL Open House Agenda 4 Questions and Discussion x'>; Questions and Discussion Download the draft plan and view the Interactive Website at: https://www.chehalisriverbasinfczd.com/cfhmp Comments? Use the comment form on the interactive website or email to betsy.dillin@lewiscountywa.gov before September 30th. 1 �/J. £.0 Questions and Discussion • In Person — Large display maps — List of actions — Flood risk map station • Compare your property location to the different 100-year floodplains • Zoom — Link to download display maps and actions — Send a private message to the host with your property address and email address, and we will email you a map. Questions and Discussion Questions? Zoom attendees — raise your hand or type in the comments! https://www.chehalisriverbasinfczd.com/cfhmp betsy.dillin@lewiscountywa.gov 1 N try+ �.� s y "`"'"4''1:" *'€ <4d 4.'a_ s ".,° ° tx r jar .,..,,„„ ,22L. ...44".ri r:+ a- i, "fl- as / `:• # k 4 �, '�t ' , lam"¢ 1 x , ;*, `+ ''`' r'# 1r i ",r ,,. � , /-.'.) -}� rya 1 .7` 1, ,'s. '1 ;' „� r at. ., i la i 4 , . !'+'r �n* z'�'�r'' * i .ter^ �� .,. v. .r • r 'i _. , . ., . ,, iv, „.. _ .,„ _. ,.... .._ ----"? ..or. ...,.,... ,..„ *0 :- r a !• 4r,..):, ,+ ...:; t f - ASO4. 4* Chehalis River Basin t{�-- = ;— i �_` Centralia ' * . flood Control Zone District * _ , .r ,, -,1 " iv Comprehensive Flood ` ` .1 •*g , �; Hazard Management Plan —,, ' . _ Centralia.Chehalis,and Napovine #.; ' Legend .e . ,. A 'A 1f iJt • J a N i I Lewis County Boundary 41f " , , • Modeled 100-Year Climate Change Floodplain ' R x Modeled 100-Year Floodploin r ri - Effective 100-Year Floodplain(FEMA) / 1; ' ' —Planning Area Watercourses ti H r +" Planning Area .► T c s OCities ` - t.'� > PERTEET0 I +e '' k <• ' iv o I 2 ` r. b " 4 Ayt . ,r, 1• 4.fi 4 4 y. fy ,, , 5 4404 , t•+w r J '' • • • t I (.11 '' -^. Tr'� � • s'' {>w. ifia t ^� d l if # .:� 14 tii", i Pi II" _ ,� Ate~ •• ti .V!, sr t' k , 6 y \N„ • Ol sat , , � t r vv. -7 4 'At Attee.`-yif f/ ''t iide.., .41. •,........ . lit'....., v.* = I _. I 1 itf r - ....- : Stearns Grcr a114 . .. ,a • sr� `+► 64riscitiolH4 3>av \ eti.- - "c 507, 0.;� Chehalis River Basin T f+l i/ `•vi411011111' Flood(tutuI Zone District ,.�-"' j — Comprehensive Flood r —ter ; ' _ - Hazard Management Plan •„v (v v1. ! , Eastern Planning Area , 41, - ..... ,. 1/anajnrArrcek i ''s'•. Legend r 41, _ Lewis County Boundary l _, _ • ) + y odeled 100 Yeor Climate Change Floodpb�n (! "'�i+• r•,dcled 100-Year Floodploin 4) ..,a �� . " oiiiiiiiisiiiir-lt.: ._ . Eticctive 100-Yeor Floodploin(FEMA) 1.124............. � i j ,h t >b#Xl v t —Planning Area Watercourses v s tt'+ Planning Area �y �_ I. �'_�ties ' PERTEET 0 '` ` " ply " - v u z 1 t . ...„._ . .,. ...•---'irk*, NiviList ''L:..- lit .� 1 fir. r• 4 . 1 • �. 41. g -'-'. ....1111/0,14 A_ --..-. • ,.• -i : . , • ,....,.. . - .1 •.%.. ,,,,,,,,, ...1_,.41. . , :. ,,; R ,. ' ' -:4 a. .... ,�r ra � -r+ ram' +�� ,�" .. t7 'r . j- "j 4 , - � -ate t -.< .104 • r. • l• •'��, r �:Ai 'rli 4.- ..L ,� �t "/ - Came, / • 0. l• •m �,»f /: _ `� �, . '� • �/y(� 'r 4.• • :';``ems pp,��,,yy- -i�li+ _ ..' ' ,� �•. " .1{ .ti. : , rrr1�1[jj+(+(ii�� .`w t t' f f jam. . .i. ,. ">rw.l g , pry 41 :AkIll f ' i ' L : ., . Ill Nir.!IC:- lore . 411 ' A.: " - p.--tfir , . . . , • .... ..,,,,„ , . 4 • 508 '' ''---. 1111110110114iP T'J mow- �•.. R ,ip ' � � I I J -Y'l_ • J.`fi 1. Nik-, a 1-,a..r0 t- -ti•4'4,•• •. JK_ . .•.•,. 1 i it _ . .J ` ._ 'Ait-s. • • .14' • r .. '�/•• 4.- r 1 -' «mot - .4 i• . .. . . -,.. I , a► t s: s�K •. • F ,, 'J J S► t :. •.; I.41: 1:: ..... . .40. _ ... tht I , . ..., , ir„, ;. , ,...,,'t trip..,40,, ; . . • _. iii- ,fir a Bunker CrreR _ �iy;�" r �... ',..r - :r• .. ti.. 1„s 6 i ri eo li _•`.k p ry1‘1''6C. .4''' ' ''it' . .,,'•• ..t. t .i.:. ,...4:0'e,'.'.i1/4...'1.6,_t'.:''.!is*n,. ., , e•li 7',.'.a„.,....6..0.; 413-1116:.7;.1. i jai- wzl f ! t►a .:g'r.r eI ll;e:ir r r.:19011111N i:.f � yl' ,i- �;' -t fir',, • '(,. 1 "" I d' " •.. . •' •,,--El.... •• •./...';4:1'9.1 ' ::...4 W.. llitTilliA , litil* 4 4 Si _-4i .7.4( -., . i /4; _;:!1:-. . • p • „,n, .• ,.A Vie. ''', , , ., ,, / i- a. . 1....y. . '.. .- 7. -14 '''• oiAr' .i lit 1. -.n> iS $ V. n � . �i,�j --,.44- - 'Pe,Ell I r 1. - .._ ; •6 _- 4 _ a 4Chehalis River Basin Ill i Flood Control Zone District s ; n itrver �!!�"\ < �'is +��" * . Comprehensive Flood ' .� * Hazard Management Plan '14 -- a.� i' .• , y+.. ,� « Western Planning Area . . a .�, �' t ,c. • ....,, r Legend y , --• I « 'ti"..‹.. A: \ r-? +? Lewis County Boundary « t s '` S a r, { doled 100•Yeor Climate Change Floodplain 1roi, -,...,_, i. t r �.. Modeled 100-Year Floodplom 4. r ita ..41,„ ` w.._ .., ..„i , . ,,,..,• Effective 100-Year Floodplo n(FEMA)• L —Planning Area Watercourses -t !� s lik Piammng Area 1 r. , PERTEET 0 VOL- 111111142/4 4 • - -j - . o t l APPENDIX D Mitigation Action Catalog 1.0 MITIGATION ACTION CATALOG The stakeholder committee evaluated the action catalog while developing the CFHMP action plan. Not all actions were included in the CFHMP. 1.1 Public Sector Actions Catalog The following actions by the public sector have the potential to mitigate the flood hazard: • Manipulate the flooding hazard: o Refrain from obstructing stormwater drains, culverts, and other related infrastructure o Increase water conservation efforts o Install localized stormwater systems • Reduce exposure to the flooding hazard: o Locate outside of hazard area o Elevate utilities above base flood elevation o Institute low impact development techniques on property o Assess projects to determine if they may inadvertently increase flood risk • Reduce vulnerability to the flooding hazard: o Retrofit house (elevate house above base flood elevation) o Elevate items within house above base flood elevation o Build new house above base flood elevation o Floodproof non-residential structures o Retrofit, protect, or replace scour-critical bridges o Replace undersized culverts • Increase the ability to respond to or be prepared for the flooding hazard: o Comply with National Flood Insurance Program o Buy flood insurance o Develop household mitigation plan, such as retrofit savings, communication capability with outside, 72-hour self-sufficiency during and after an event o Be aware of evacuation routes o Educate yourself on flood risk from related hazards, such as wildfire o Participate in Community Emergency Response Team training when available. 1.2 Private Sector Actions The following actions by the private sector have the potential to mitigate the flood hazard: • Manipulate the flooding hazard: o Refrain from obstructing stormwater drains, culverts, and other related infrastructure o Increase water conservation efforts o Install localized stormwater systems 1 • Reduce exposure to the flooding hazard: o Locate business critical facilities or functions outside hazard area o Institute low impact development techniques on property o Assess projects to determine if they may inadvertently increase flood risk • Reduce vulnerability to the flooding hazard: o Build redundancy for critical functions; retrofit critical buildings o Provide flood-proofing measures when new critical infrastructure must be located in flood hazard areas • Increase the ability to respond to or be prepared for the flooding hazard: o Increase capability by having cash reserves for reconstruction o Support and implement hazard disclosure for the sale of property in identified risk zones o Solicit cost-sharing through partnerships with other private or public sector stakeholders on projects with multiple benefits 1.3 Government Sector Actions The following actions by governments have the potential to mitigate the flood hazard: • Manipulate the flooding hazard: o Improve stormwater systems o Maintain stormwater drains, culverts, and other related infrastructure o Perform dredging and levee construction/maintenance, providing retention areas o Provide/maintain structural flood control: levees, dams, channelization, revetments o Construct regional stormwater facilities o Stabilize areas with significant erosion concerns o Promote/retain natural vegetation in areas with significant erosion concerns o Increase water conservation efforts o Continue to pursue holistic flood hazard management and opportunities for promoting or preserving natural floodplain function • Reduce exposure to the flooding hazard: o Continue to coordinate with the Chehalis Basin Strategy and Chehalis River Basin Flood Authority o Locate or re-locate critical facilities outside of hazard areas o Acquire or relocate structures from identified governmental repetitive loss properties o Promote open space uses in identified high hazard areas via techniques such as planned unit developments, easements, setbacks,greenways,or sensitive area tracks o Adopt land development criteria such as planned unit developments, density transfers and clustering o Institute low impact development techniques on property o Acquire vacant land or promote open space uses in developing watersheds to control increases in runoff o Perform a buildable lands analysis to determine areas where exposure may increase 2 o Comply and work with provisions protecting endangered species within the County • Reduce vulnerability to the flooding hazard: o Strengthen existing infrastructure o Provide redundancy for critical functions and infrastructure o Adopt appropriate regulatory standards, such as cumulative substantial improvement/damage,freeboard, lower substantial damage threshold and compensatory storage o Adopt/enhance stormwater management regulations and master planning o Adopt no-adverse-impact flood hazard management policies that strive to avoid increasing the flood risk on downstream communities o Encourage mitigation of private property o Perform regular inspections and assessments of locally owned or maintained flood control infrastructure o Replace undersized culverts o Provide permanent protection for pump stations at risk of flooding o Identify and mitigate drainage issues resulting in ponding o Enhance road drainage programs o Ensure that the permitting process is consistent with the adopted flood hazard development ordinance o Elevate or relocate roads subject to frequent flooding o Retrofit, protect, or replace scour critical bridges o Develop guidelines for floodplain fringe protections o Increase freeboard regulations o Account for changing climate conditions in relevant codes o Develop and assist in maintenance of emergency warning systems • Increase the ability to respond to or be prepared for the flooding hazard: o Produce more accurate flood hazard maps or identify areas for further study o Provide technical information and guidance o Enact tools to help manage development in hazard areas (stronger controls,tax incentives, information, enforcement of the NFIP) o Include retrofit or replacement of critical systems in capital improvement programs o Develop strategy to take advantage of post-disaster opportunities o Warehouse critical infrastructure components o Develop and adopt a continuity of operations plan o Improve and build on Community Rating System program classification o Maintain existing data and gather new data needed to define risks and vulnerability o Provide training for staff and decision-makers in flood hazard management o Develop and implement a public information strategy o Integrate flood hazard management policies into other local planning mechanisms o Develop and maintain a system for perishable data collection after a flood event 3 o Develop a framework and continue efforts for cooperation between agencies and districts in flood mitigation activities (e.g. sand and sandbag deployment) o Retain good standing in National Flood Insurance Program o Integrate flood mitigation opportunities into capital improvement programs o Identify funding sources and opportunities o Create a fund or earmark funds for in-kind contributions as grant opportunities become available o Produce after-action reports on flood events o Develop and update evacuation routes o Participate in information sharing with other agencies (e.g. Corps of Engineers, NWS) o Develop and update memorandums of understanding with other local jurisdictions and continue to coordinate emergency response and preparedness activities o Identify sources of nuisance flooding o Review and, if needed, update flood hazard development ordinances o Require or encourage rapid damage assessment training o Map locations of storm drains, catch basins, dry-wells and other stormwater infrastructure so they may be maintained and cleared when needed o Identify debris collection sites o Continue to develop post-fire outreach strategies for impacted residents o Develop public outreach materials o Educate residents on types of projects that may inadvertently increase flood risk o Educate residents on the nexus between water conservation, drought, and flood o Continue to identify opportunities for partnerships o Promote the Flood Control Zone District as a taxing authority to generate funding or identify sustainable funding solutions o Support and implement hazard disclosure for the sale of property in identified risk zones and increase enforcement of disclosure provisions o Map and create an inventory of open spaces with potential for beneficial functions o Incorporate invasive species management into flood hazard management activities o Continue improving upon emergency services capabilities and public awareness of preparedness o Sponsor/encourage/promote local Community Emergency Response Team activities o Identify and monitor drainage problem areas 4 APPENDIX E Annual Progress Report Template Lewis County, Washington Chehalis River Basin Comprehensive Flood Hazard Management Plan Annual Progress Report Reporting Period: (Insert reporting period) Background: Lewis County developed a Chehalis River Basin Comprehensive Flood Hazard Management Plan to reduce risk from flooding through identified resources, information, and strategies.To prepare the plan, Lewis County organized resources,assessed risks from flooding,developed planning goals and objectives, reviewed mitigation alternatives, and developed an action plan to address probable impacts from floods.The plan can be viewed on-line: [WEBISTE LINK]. Purpose:The purpose of this report is to provide an annual update on the implementation of the action plan identified in the Chehalis River Basin Comprehensive Flood Hazard Management Plan. The objective is to ensure that there is a continuing and responsive planning process that will keep the floodplain management plan dynamic and responsive to the needs and capabilities of Lewis County and its stakeholders.This report discusses the following: • Flood events that have occurred within the last year • Changes in risk exposure within the planning area • Mitigation success stories • Changes in capabilities that could impact plan implementation • Floodplain management plan implementation status • Review of the action plan • Recommendations for changes/enhancement Flood Events within the Planning Area: During the reporting period,there were # flood events in the planning area that had a measurable impact on people or property.A summary of these events is as follows: (Include a narrative of each flood event. What type of flood event?When it occurred?Where it occurred?How long did it last? What types of damages did it do?) Changes in Risk Exposure in the Planning Area:(Insert an overview of any flood event in the planning area that changed the probability of occurrence of flooding as presented in the floodplain management plan) Mitigation Success Stories:(Insert an overview of mitigation accomplishments during the reporting period, including notably successful public outreach efforts) Changes That May Impact Implementation of the Flood Plan:(Insert an overview of any significant changes in the planning area that would have a profound impact on the implementation of the plan or on public outreach efforts.Specify any changes in technical,regulatory,and financial capabilities identified during the plan's development) 1 Floodplain Management Plan Progress Summary Overview of the Flood Plan's Progress:The performance period for the floodplain management plan became effective on , 2021 with the adoption of the Flood Plan by the Lewis County Board of Commissioners.The initial performance period for this plan will be five years, with an anticipated update to the plan to occur before , 2026.As of this reporting period,the performance period for this plan is considered to be %complete.The floodplain management plan has targeted # flood hazard mitigation actions to be pursued during the five-year performance period.As of the reporting period,the following overall progress can be reported: out of_actions ( %) reported ongoing action toward completion. out of_actions(_%)were reported as being complete. out of_actions (_%) reported no action taken. The Floodplain Management Plan Stakeholder Committee:The floodplain management plan Stakeholder Committee, made up of stakeholders within the planning area, reviewed and approved this progress report at its annual meeting held on , 2022. It was determined through the plan's development process that the Stakeholder Committee would remain in service to oversee maintenance of the plan.At a minimum,the Stakeholder Committee will provide technical review and oversight on the development of the annual progress report. It is anticipated that there will be turnover in the membership annually, which will be documented in the progress reports. For this reporting period,the Stakeholder Committee membership is as indicated in Table 1. Table 1.Stakeholder Committee Members. Name Title Jurisdiction/Agency 2 Review of the Action Plan:Table 2 reviews the action plan,reporting the status of each initiative. Reviewers of this report should refer to the floodplain management plan for more detailed descriptions of each initiative and the prioritization process. Address the following in the "status"column of the following table: Was any element of the initiative carried out during the reporting period? If no action was completed, why? Is the timeline for implementation for the initiative still appropriate? If the initiative was completed, does it need to be changed or removed from the action plan? Table 2.Action Plan Matrix. Action Taken? Timeline Priority Status Status (Yes or No) (X,0,©) Initiative# — [description] 1 1 I 1 Initiative# — [description] Initiative# — [description] 1 1 Initiative# — [description] I 1 Initiative# — [description] 1 Initiative# — [description] 1 I 1 Initiative# — [description] I Initiative# — [description] I Initiative# — [description] Initiative# — [description] 1 I 1 Initiative# — [description] 1 I I Initiative# — [description] 1 I I Initiative# — [description] I I I Initiative# — [description] 1 I I Initiative# — [description] 1 I Initiative# — [description] 3 Initiative# — [description] Initiative# — [description] Initiative# — [description] Initiative# — [description] I I Initiative# — [description] Initiative# — [description] Initiative# — [description] I I Initiative# — [description] Completion status legend: lI = Project Completed 0=Action ongoing toward completion X= No progress Recommendations for Changes or Enhancements: Based on the review of this report by the floodplain management plan Stakeholder Committee,the following recommendations will be noted for future updates or revisions to the plan: PUBLIC REVIEW NOTICE The contents of this report are public knowledge and have been prepared for total public disclosure. Copies of the report have been provided to the Lewis County Board of County Commissioners and to local media outlets and the report is posted on the floodplain management plan website.Any questions or comments regarding the contents of this report should be directed to: Chehalis River Basin Flood Control Zone District 351 NW North Street Chehalis,WA 98532 (360)740-2697 [EMAIL] 4 BOCC AGENDA ITEM SUMMARY Resolution: 21-422 BOCC Meeting Date: Nov. 30, 2021 Suggested Wording for Agenda Item: Agenda Type: Hearing - Resolution Approving and adopting the 2021 Comprehensive Flood Hazard Management Plan (CFHMP) Contact: Erik Martin Phone: 3607402697 Department: BOCC - Board of County Commissioners Description: Approving and adopting the 2021 Comprehensive Flood Hazard Management Plan (CFHMP) Approvals: Publication Requirements: Publications: User Status Lee Napier Pending PA's Office Pending Additional Copies: Cover Letter To: Betsy Dillin Kirk Holmes, Christina Wollman