2023_Washington_County_NHMP_Combined_Final_3.21.23.pdf

MARCH 2023

NATURAL HAZARD

MITIGATION PLAN

WASHINGTON COUNTY, OREGON

Washington County Natural Hazard Mit igat ion Plan March 2023

Release Statement and Record of Plan Distribution i

Release Statement

Upon approval by Federal Emergency Management Agency (FEMA) Region 10 and adoption by the participating jurisdictions and special districts within the planning area, the entire document, or any specific part, may be released to the agencies or organizations determined by the Washington County, Oregon, Natural Hazard Mitigation Plan (NHMP) Steering Committee.

Release to the public of the entirety or any part of this document will follow current state and local public information statutes and practices.

Record of Plan Distribution

Table 1: Record of Plan Distribution

Number Agency Contact Name Position/Title Date

Record of Changes ii

Record of Changes

The 2023 Washington County, Oregon, Multi-Jurisdiction Natural Hazard Mitigation Plan (NHMP) is a dynamic document that is under continual review. The document may be changed administratively under the authority of Washington County Emergency Management, the administrative agency responsible for the update, in coordination with the Steering Committee.

Administrative changes may include:

Corrections or revisions that clarify context and readability;

Updates that reflect adopted policy and/or procedures;

Hazard data and risk information that enhances the current plan; and

Other authorized changes granted to the administrative agency by the Steering Committee.

It shall be the responsibility of the administrative agency’s point of contact (POC) or their designee to maintain this record of changes throughout the current planning cycle.

Table 2: Description of Changes

Section/Page Description of Change Authorized by Date

Executive Summary iii

Executive Summary

Hazard mitigation is any sustained action that reduces or eliminates long-term risk to people and property from natural hazards and their effects.

The impact of anticipated yet unpredictable natural events can be reduced through holistic planning and implementation of cost-effective, preventive mitigation efforts.

Washington County and its cities and special districts understand that it is not only less costly to reduce vulnerability to disasters than to repeatedly repair damage, but that proactive steps should be taken where possible to protect the economy, environment, and most vulnerable citizens from inevitable natural hazard events.

This NHMP recognizes that local jurisdictions and special districts have the opportunity to address their vulnerability more comprehensively by identifying mitigation strategies during all phases of emergency management (preparedness, mitigation, response, and recovery). Though hazards cannot be eliminated, vulnerability to hazards can be reduced by improving understanding of the natural hazards faced and their potential impacts and by implementing mitigation strategies.

The 2023 NHMP presents the hazard impacts most likely to affect Washington County, including its cities and special districts, and mitigation strategies to reduce or eliminate the most significant vulnerabilities.

This update to the 2017 Washington County NHMP adds eight new plan participants and the hazards of dam failure and extreme heat. It also provides updated hazard and risk data and analyses, mitigation strategies, and plan implementation details. The plan provides strategic direction to mitigate hazards and protect people, property, and the environment and increase resilience.

The plan fulfills the requirements of the Federal Disaster Mitigation Act of 2000 (DMA 2000) as administered by the Oregon Department of Emergency Management and FEMA. The project was funded by the Fiscal Year 2019 FEMA Pre-Disaster Mitigation Grant (PDMC-PL-10-OR-2019-002). An Emergency Management Coordinator at the Washington County Department of Land Use and Transportation administered the grant and led the project.

The planning area for this plan is for Washington County, Oregon, and the planning participants include the following jurisdictions and special districts:

City of Beaverton1

City of Cornelius2, 3

City of Forest Grove2, 3

City of Hillsboro

City of North Plains2

City of Sherwood2

1 The City of Beaverton NHMP was adopted in 2020. This plan was updated and incorporated into the 2023 Washington County plan as the City’s annex.

2 Did not participate in the 2017 Washington County NHMP.

3 The cities of Cornelius and Forest Grove had a joint NHMP that was adopted in September 2011. The 2011 plan was updated and incorporated into this plan as separate annexes for the cities.

Executive Summary iv

City of Tigard

Clean Water Services2

Tualatin Hills Park & Recreation District2

Tualatin Valley Water District2

Washington County

Figure 1 shows the locations of all participating jurisdictions and the service areas of participating special districts. The unincorporated areas of the county fall under Washington County’s purview.

Figure 1: Washington County Natural Hazards Mitigation Plan Planning Area

The NHMP Steering Committee identified the following hazards as impacting the planning area. These hazards are profiled in Volume 1, Section 2 of this plan, and specific hazard risk and vulnerability information unique to each participant is presented in the respective participant annexes. These hazards are shown in alphabetical order and do not represent the probability, vulnerability, or hazard risk rank identified during the planning process.

Dam failure4

Drought

Earthquake

4 New hazard for the 2023 NHMP update

Executive Summary v

Extreme heat5

Flooding

Landslide

Volcanic ash

Wildland fire

Windstorm, including tornado

Winter storm

Data collection periods during the planning process varied for planning participants, depending on their previous NHMP participation, and are shown in Table 3.

Table 3: Data Collection Periods for Planning Participants

Participant Data Collection Period

From To

Washington County and the cities of Tigard and Hillsboro 11/1/2016 2/22/2022 City of Beaverton 1/1/2020 2/22/2022 Cities of Cornelius and Forest Grove 9/1/2011 2/22/2022 All other participants As far back as was available 2/22/2022

The format of this plan is designed to provide a user-friendly source for all hazard information for participants.

Release Statement

Record of Plan Distribution

Record of Changes

Executive Summary

Abbreviations and Acronyms

Table of Contents

Volume I: Natural Hazards Base Plan

Section 1: Introduction

Section 2: Hazard Identification and Risk Assessment

Section 3: Mitigation Strategy

Section 4: Plan Execution, Maintenance, and Adoption

Volume II: Planning Participant Annexes

Annex A: City of Beaverton

Annex B: City of Cornelius

5 New hazard for the 2023 NHMP update

Executive Summary vi

Annex C: City of Forest Grove

Annex D: City of Hillsboro

Annex E: City of North Plains

Annex F: City of Sherwood

Annex G: City of Tigard

Annex H: Clean Water Services

Annex I: Tualatin Hills Park & Recreation District

Annex J: Tualatin Valley Water District

Annex K: Washington County

Volume III: Appendices

Appendix A: Planning Area Profile

Appendix B: Planning Process and Public Engagement

Appendix C: Implementation Resources and Funding Opportunities

The Washington County 2023 NHMP will be a useful tool for all participants, communities, and their stakeholders for increasing public awareness about local hazards and risks while providing information about options and resources available to reduce those risks. Informing the public about potential hazards will enable informed decision making on where to live, purchase property, or locate businesses and will help each of the jurisdictions and special districts protect themselves against the effects of the identified hazards.

Abbreviations and Acronyms vii

Abbreviations and Acronyms

AEBM Hazus Advanced Engineering Building Module

APA Approved Pending Adoption

ARPA American Rescue Plan Act

ASOS automated surface observing systems

AWIA America’s Water Infrastructure Act of 2018

BCD Oregon Building Codes Division

BFE base flood elevation

BRIC Building Resilient Infrastructure and Communities Grant Program

CARES Coronavirus Aid, Relief, and Economic Security Act CDBG Community Development Block Grant CDC Centers for Disease Control and Prevention

CDC Community Development Code

CERT Community Emergency Response Team

CFR Code of Federal Regulations

CIG Conservation Innovation Grants

CPAWC Cooperative Public Agencies of Washington County

CSZ Cascadia Subduction Zone

CVO United States Geological Survey-Cascades Volcano Observatory

CWPP community wildfire protection plan

CWS Clean Water Services

DLCD Oregon Department of Land Conservation and Development

DMA 2000 Disaster Mitigation Act of 2000

DOGAMI Oregon Department of Geology and Mineral Industries

DOT Department of Transportation DR Major federal disaster declaration

DSCI Drought Severity and Coverage Index

EAP emergency action plan

EM Federal emergency declaration

EMC Washington County Emergency Management Cooperative

EMPG Emergency Management Performance Grant

ENSO El Niño Southern Oscillation

ERP Emergency Response Plan

Abbreviations and Acronyms viii

ERT Emergency Response Team

EO Executive Order

EPA Environmental Protection Agency

FEMA Federal Emergency Management Agency

FIRM Flood Insurance Rate Map

FM Federal fire management assistance declaration

FMA Flood Mitigation Assistance

FPA floodplain administrator

FWS Fish and Wildlife Service

G acceleration due to gravity

GIS geographic information system HAZMAT hazardous materials

Hazus-MH Hazards U.S. Multi-Hazard software

HMA Hazard Mitigation Assistance

HMPG Hazard Mitigation Grant Program

HOA Home Owners Association

HUD Housing and Urban Development (Department of)

HVAC heating, ventilation, and air conditioning system

ISO Insurance Services Office

JWC Joint Water Commission

MGD million gallons per day

MM Modified Mercalli Intensity Scale

MPH miles per hour

NEHRP National Earthquake Hazards Reduction Program

NEPA National Environmental Policy Act

NFP National Fire Plan NFIA National Flood Insurance Act NFIP National Flood Insurance Program

NHMP Natural Hazard Mitigation Plan, Washington County, Oregon Multi-Jurisdiction Natural Hazard Mitigation Plan

NID National Inventory of Dams

NOAA National Oceanic and Atmospheric Administration

NPS National Park Service

NRCS National Resources Conservation Service

NSF National Science Foundation

NWS National Weather Service

ODF Oregon Department of Forestry

Abbreviations and Acronyms ix

OEM Oregon Department of Emergency Management

ORWARN Oregon Water/Wastewater Agency Response Network

OWEB Oregon Watershed Enhancement Board

OWRD Oregon Water Resources Department

P primary seismic waves

PA Public Assistance

PDM Pre-Disaster Mitigation Grant Program

PGA peak ground acceleration

PG&E Pacific Gas and Electric Company

PNW Pacific Northwest region of the United States, which includes Washington County

POC point of contact

RDPO Regional Disaster Preparedness Organization

RFO Regulatory Floodplain Overlay

RL repetitive loss property

RWPC Regional Water Providers Consortium

S secondary seismic waves

SBA Small Business Administration SBA EIDL Small Business Administration Economic Injury Disaster Loan

SCADA supervisory control and data acquisition software

SFHA Special Flood Hazard Area

SFIP Standard Flood Insurance Policy

SHMO state hazard mitigation officer

SRL severe repetitive loss property

SWSI Surface Water Supply Index from the Natural Resources Conservation Service

TMDL total maximum daily load THPRD Tualatin Hills Park & Recreation District

TVF&R Tualatin Valley Fire and Rescue TVWD Tualatin Valley Water District

URM unreinforced masonry structures

USACE U.S. Army Corps of Engineers

USDA United States Department of Agriculture

VEI Volcanic Explosivity Index

WUI Wildland-urban interface

WWSP Willamette Water Supply Program WWSS Willamette Water Supply System

°F Degrees Fahrenheit

Table of Contents x

Table of Contents

Volume I: Natural Hazards Base Plan

Volume II: Planning Participant Annexes

Annex A: City of Beaverton

Annex B: City of Cornelius

Annex C: City of Forest Grove

Annex D: City of Hillsboro

Annex E: City of North Plains

Annex F: City of Sherwood

Annex G: City of Tigard

Annex H: Clean Water Services Placeholder

Annex I: Tualatin Hills Park & Recreation District

Annex J: Tualatin Valley Water District

Annex K: Washington County

Volume III: Appendices

Appendix A: Planning Area Profile

Appendix B: Planning Process and Public Engagement

Appendix C: Implementation Resources and Funding Opportunities https://ieminc4-my.sharepoint.com/personal/jill_turner_ieminc_com/Documents/Documents/0%20-%20Projects/2022/WASHCO%20HMP/00000%20-%20FINAL%20DOCUMENTS/WashCo.NHMP_COMBINED_Final_3.21.23_jt.docx#_Toc130290418 https://ieminc4-my.sharepoint.com/personal/jill_turner_ieminc_com/Documents/Documents/0%20-%20Projects/2022/WASHCO%20HMP/00000%20-%20FINAL%20DOCUMENTS/WashCo.NHMP_COMBINED_Final_3.21.23_jt.docx#_Toc130290419 https://ieminc4-my.sharepoint.com/personal/jill_turner_ieminc_com/Documents/Documents/0%20-%20Projects/2022/WASHCO%20HMP/00000%20-%20FINAL%20DOCUMENTS/WashCo.NHMP_COMBINED_Final_3.21.23_jt.docx#_Toc130290431

MARCH 2023

Volume I: Natural Hazards Base Plan

Section 1: Introduction 1

1. Introduction

Code of Federal Regulations (CFR) Title 44, Part 201.6 (44 CFR §201.6) Requirements §201.6(c)(3)(i): [The hazard mitigation strategy shall include a] description of mitigation goals to reduce or avoid long-term vulnerabilities to the identified hazards.

§201.6(c)(4)(i): [The plan maintenance process shall include a] section describing the method and schedule of monitoring, evaluating, and updating the mitigation plan within a five-year cycle.

What is Hazard Mitigation?

Mitigation is commonly defined as sustained actions taken to reduce or eliminate long-term risk to people and property from hazards and their effects. Hazard mitigation focuses attention and resources on policies and actions that will produce benefits over time.

A mitigation plan states the specific courses of action that participants intend to follow to reduce vulnerability and exposure to future hazard events. These plans are formulated through a systematic process centered on the participation of individuals, businesses, public officials, and other stakeholders.

A local hazard mitigation plan documents the jurisdiction’s commitment to reduce risks from natural hazards. Local officials can refer to the plan in their day-to-day activities and in decisions regarding regulations and ordinances, granting permits, and funding capital improvements and other community initiatives. Additionally, local plans serve as the basis for states to prioritize grant funding.

To reduce the nation’s mounting natural disaster losses, the United States Congress passed the Disaster Mitigation Act of 2000 (DMA 2000) to amend the Robert T. Stafford Disaster Relief and Emergency Assistance Act (Stafford Act) of 1988. Section 322 of DMA 2000 emphasizes the need for state and local government entities to closely coordinate mitigation planning activities and makes the development of a hazard mitigation plan a specific eligibility requirement for any local government applying for federal mitigation grant funds. These funds include the Hazard Mitigation Grant Program, and the Building Resilient Infrastructure and Communities grant program (formerly known as the Pre-Disaster Mitigation grant program) administered by the Federal Emergency Management Agency (FEMA) under the Department of Homeland Security. Communities with an adopted and federally approved hazard mitigation plan thereby become pre-positioned and more apt to receive available mitigation funds before and after the next disaster strikes.

1.1. Overview

Local hazard mitigation planning is the process of organizing community resources, identifying and assessing hazard risks, and determining how to best minimize or manage those risks. This process results in a hazard mitigation plan that identifies specific mitigation actions, each designed to achieve both short-term planning objectives and a long-term risk reduction. To ensure the functionality of each mitigation action, responsibility is assigned to a specific individual, department, or agency along with a schedule for its implementation. The plan maintenance process and procedures are established with an eye toward developing an ongoing assessment and monitoring of implementation progress, as well as the evaluation and enhancement of the mitigation plan itself. These plan maintenance procedures ensure the plan remains a current, dynamic, and effective planning document over time.

Section 1: Introduction 2

Mitigation planning offers many benefits, including the following:

Awareness of risks and vulnerabilities for decision makers, planners, and the public.

Saving lives, property, environments, and money.

Reduction of hazard impacts and faster recovery following disasters, which enhances resilience.

Creation of strong community partnerships across sectors and with the public.

Reduction of future vulnerability through wise development and post-disaster recovery and reconstruction.

Expediting the receipt of pre-disaster and post-disaster grant funding.

Integration of mitigation actions into other local planning efforts, goals, and initiatives.

The 2023 NHMP has been prepared in coordination with the offices of FEMA Region 10 and the Oregon Department of Emergency Management (OEM) to ensure that it meets all applicable DMA 2000 and state requirements. A Local Mitigation Plan Review Tool, found in Volume III, Appendix B, provides a summary of federal minimum planning standards, and notes the location in this plan where each requirement is met.

1.2. Background

The most recent update of the Washington County NHMP was adopted in 2017. The 2017 Washington County NHMP participants included the cities of Hillsboro and Tigard. and was adopted by the Washington County Board of County Commissioners on November 22, 2016. The city of Beaverton updated its NHMP in 2020, and it was adopted by the Beaverton City Council on April 28, 2020. The city of Beaverton opted to join the 2023 Washington County NHMP update as did seven other new participants, for a total of eight new participants. This update adds dam failure and extreme heat as hazards that impact the planning area.

1.3. Purpose

Hazard mitigation plans are prepared and adopted by communities with the primary purpose of identifying, assessing, and reducing long-term risk to life and property from hazard events. Effective mitigation planning can break the cycle of disaster damage, reconstruction, and repeated damage by natural hazards in the following ways:

Identifying how a community will work together to reduce risks which will protect life, safety, and property by reducing the potential for future damages and economic losses that result from all hazards.

Improve public awareness of the need for individual preparedness and building safer, more disaster-resilient communities.

Make communities safer places to live, work, and play.

Qualify for grant funding in both the pre-disaster and post-disaster environments.

Develop strategies for long-term community sustainability during community disasters, which will speed recovery and redevelopment following future disaster events.

Demonstrate a firm local commitment to hazard mitigation principles.

Comply with state and federal requirements for local multi-jurisdictional hazard mitigation plans.

Section 1: Introduction 3

1.4. Authority and Guidance

This plan was prepared in compliance with Section 322 of the Stafford Act, 42 U.S.C. 5165, as amended by Section 104 of the DMA 2000. Local mitigation planning requirements are codified in the Code of Federal Regulations (CFR) Title 44, Part 201.6 (44 CFR §201.6), Local Mitigation Plans. DMA 2000 specifies requirements for local governments to undertake a risk-based approach to reducing the impacts and consequences from natural hazards through mitigation planning. In addition, DMA 2000 requires that local plans be updated every five years, with each planning cycle requiring a complete review, revision, and approval of the plan by the state and FEMA.

The plan shall be routinely monitored, evaluated, and revised to maintain compliance with the following provisions, rules, and legislation:

Section 322, Mitigation Planning, of the Stafford Act, as enacted by Section 104 of the DMA 2000 (Public Law 106-390); and

FEMA’s Interim Final Rule published in the Federal Register on February 26, 2002, 44 CFR §201.

The method and schedule for plan maintenance is provided in additional detail in Volume I, Section 4.

1.5. Applicability and Scope

The scope of this NHMP encompasses all participating entities in Washington County, as noted in the Executive Summary. This plan identifies natural hazards that could threaten life, property, and the environment throughout the County. The scope of this plan includes both short- and long-term mitigation strategies, implementation strategies, and possible sources of project funding to mitigate identified hazards. This plan complements and is consistent with the 2020 State of Oregon Natural Hazard Mitigation Plan (2020 Oregon NHMP) and builds on and updates the 2017 Washington County NHMP.

The information provided in the Hazard Identification and Risk Assessment (Volume I, Section 2) reflects the impact of the hazards on all of Washington County, not solely the participating entities. Additionally, the historical events documented in Volume I, Section 2 reflect the events that impacted the entire county, not solely the unincorporated areas of the County. Participant-specific vulnerability analyses, risk assessments, and historical events are in the individual participant annexes.

1.6. Policy Framework for Natural Hazards Planning in

Oregon Planning for natural hazards is an integral element of Oregon’s statewide land use planning program, which began in 1973. All Oregon cities and counties have comprehensive plans and implementing ordinances that are required to comply with the statewide planning goals. The challenge faced by state and local governments is to keep this network of local plans coordinated in response to the changing conditions and needs of Oregon communities.

The Oregon Statewide Land Use Planning Goal 7, Areas Subject to Natural Hazards, calls for local plans to include inventories, policies, and ordinances to guide development in hazard areas. Planning Goal 7, along with other land use planning goals, has helped reduce losses from natural hazards. Through risk identification and the recommendation of risk reduction actions, the 2023 NHMP aligns with the goals of the comprehensive plans for Washington County and all participating cities, and the Tualatin Valley Water District Master Plan, and helps all participants meet the requirements of Planning Goal 7.

The primary responsibility for the development and implementation of risk reduction strategies and policies lies with local jurisdictions. However, resources exist at the state and federal levels. Some of the key agencies at these levels include OEM, Oregon Building Codes Division, Oregon Department of

Section 1: Introduction 4

Forestry (ODF), Oregon Department of Geology and Mineral Industries (DOGAMI), and the Department of Land Conservation and Development.

1.7. Plan Development and Update Process

This plan update was facilitated, written, and completed in collaboration with the contracting firm IEM. The project was funded by Fiscal Year 2019 FEMA Pre-Disaster Mitigation Grant (PDMC-PL-10-OR-2019- 002). The grant was administered, and the project led by, an Emergency Management Coordinator at the Washington County Department of Land Use and Transportation. Additional information about the plan development and update process, including public engagement opportunities and outcomes, is in Volume III, Appendix B.

1.8. Mitigation Goals

The Steering Committee reviewed and evaluated goals from the 2017 Washington County NHMP, 2020 city of Beaverton NHMP, 2011 NHMP for the cities of Cornelius and Forest Grove, and 2020 Oregon NHMP. The goals from each plan were grouped by topic and then synthesized to create the seven goals below. These goals are the basis of this plan and summarize what the Steering Committee will accomplish by implementing this plan.

1. Develop and implement strategies to minimize loss of life, public and private property damage, and damage and disruption of essential infrastructure from the impact of natural hazards while protecting and restoring the environment.

2. Ensure effective implementation of mitigation strategies and increased success in receiving funding. This includes:

a. Develop and maintain partnerships and promote mitigation leadership within local and regional public agencies; the public; non-profit organizations; and businesses.

b. Ensure consistency between city, county, regional, and state mitigation strategies.

c. Consistently seek diverse funding and resource partnerships for future mitigation efforts.

3. Develop and implement natural hazard education and outreach programs to increase awareness, engagement, and partnership among the public; local, city, and regional agencies; nonprofit organizations; and businesses. Includes:

a. Engage and motivate the public to invest in natural hazard risk reduction policies and projects.

b. Motivate the “whole community” to build resilience and mitigate against the effects of natural hazards through engagement, listening, learning, information-sharing, and funding opportunities.

4. Support the adoption and application of development policies and standards that address the potential impacts of natural disasters and prevent development within mapped hazardous areas where risks to people and property cannot be practicably mitigated.

5. Enhance communication, collaboration, and coordination among agencies at all levels of government and the private sector to mitigate natural hazard risks.

6. Integrate and align hazard mitigation strategies with local comprehensive plans, climate adaptation efforts, and emergency operations plans and procedures, when possible.

7. Enhance the ability of the economies of Washington County and its jurisdiction to rebound quickly from natural hazard events, by strengthening emergency operations including increasing communication, collaboration, and coordination among public agencies, non-profit organizations, and businesses. Includes mitigating the inequitable impacts of natural hazards by prioritizing and directing resources and investments to build resilience in the most vulnerable populations and the communities least able to respond and recover.

Section 1: Introduction 5

1.9. Plan Organization, Format, and Content

The NHMP is organized into three volumes that satisfy the mitigation requirements in 44 CFR §201.6.

Volume I has four sections, each participant annex in Volume II has six sections, and Volume III has three appendices containing supporting documentation.

Volume I

The following sections are included in Volume I:

Section 1: Introduction

Describes the purpose of the NHMP and introduces the mitigation planning process.

Section 2: Hazard Identification and Risk Assessment

Describes the hazards identified, location of hazards, previous events, and jurisdictional profiles, satisfying the requirements under 44 CFR Parts 201.6(c)(2)(i) and 201.6(c)(2)(ii).

Section 3: Mitigation Strategy

Reflects on the mitigation actions previously identified and examines the ability of participating entities to implement and manage a comprehensive mitigation strategy, satisfying the requirements under 44 CFR Parts 201.6(b)(3), 201.6(c)(1), 201.6(c)(3)(i), 201.6(c)(3)(ii), 201.6(c)(3)(iii), 201.6(c)(3)(iv), and 201.6(c)(4)(ii), and

Section 4: Plan Execution, Maintenance, and Adoption

Describes strategies for monitoring, evaluating, and updating plans; NHMP incorporation into other plans and policies; and future public updates for each participating jurisdiction, satisfying the requirements under 44 CFR Parts 201.6(c)(4)(i), 201.6(c)(4)(ii), and 201.6(c)(4)(iii).

Volume II

Volume II includes eleven participant annexes. Each participant annex contains six sections that satisfy the requirements under 44 CFR Parts 201.6(b)(1), 201.6(b)(2), 201.6(b)(3), 201.6(c)(1), 201.6(c)(2)(i), 201.6(c)(2)(ii), 201.6(c)(4)(i), and 201.6(c)(4)(iii).

Section 1: Introduction

Section 2: Planning Process

Section 3: Hazard Identification and Risk Assessment

Section 4: Capability Assessment

Section 5: Mitigation Strategy

Section 6: Action Items

Volume III

Volume III comprises the following three appendices:

Appendix A: Planning Area Profile

Appendix B: Planning Process and Public Engagement

Section 1: Introduction 6

Describes the planning process and organization for each participating jurisdiction, satisfying the requirements of 44 CFR Parts 201.6(b)(1), 201.6(b)(2), 201.6(b)(3), 201.6(c)(1), 201.6(c)(4)(i), and 201.6(c)(4)(iii).

Appendix C: Implementation Resources and Funding Opportunities

1.10. Maintenance Process

The Steering Committee, consisting of a representative from each participating jurisdiction and special district, will continue to collaborate as a planning group in coordination with the Washington County NHMP Project Manager. Primary contact will be through emails and conference calls, with strategy meetings occurring at least annually and following a disaster declaration for natural hazards covered in this plan for any planning participants. The Steering Committee points of contact for the participants will jointly lead the plan maintenance and update process by:

Discussing methods for continued public involvement and education;

Documenting successes and lessons learned;

Researching new or updated data, laws, policies, regulations, or initiatives that can contribute to hazard histories, risk assessments, loss estimates, vulnerabilities of assets, or action items for plan participants;

Reviewing potential funding availability, including state and federal grant program Notices of Funding Opportunities;

Assessing the progress of previously implemented actions that reduce vulnerability and losses, and any new opportunities for mitigation actions; and

Maintaining and completing documentation of the NHMP maintenance process.

Each Steering Committee member is responsible for monitoring and tracking the progress of action items identified by their jurisdiction or special district in this NHMP and submitting a status summary to the County’s project manager biannually using the action item planning document.

Additionally, each Steering Committee member will work with their Technical Committee and other jurisdictional or special district representatives to:

Review existing action items to determine appropriateness for local funding;

Prioritize potential mitigation projects; and

Update decision makers on progress of the plan.

1.11. Plan Approval and Adoption Process

Once the NHMP has received FEMA Approvable Pending Adoption (APA) status, each participating jurisdiction or special district will take the plan to their governing body for final public comment and adoption. A copy of each adoption resolution will be inserted into Volume III, Appendix B and held on file at FEMA, OEM, and the Washington County Emergency Management Office.

Section 2: Hazard Identification and Risk Assessment 7

2. Hazard Identification and Risk Assessment

Significant Changes Detailed information on the OEM hazard analysis methodology included.

Dam failure, extreme heat, and wildfire smoke added as hazards impacting the planning area.

Disaster declarations expanded to include federal, state, and local declarations.

Summary table of participant hazard risk scores for all hazards added.

Information on characteristics, location, extent, history, probability of future events, vulnerabilities, and how climate change may impact frequency and or intensity added for all natural hazards in the planning area.

Updated all tables and figures to reflect current information.

Inclusion of additional maps and graphics showing hazard information.

Drought hazard profile expanded to include ecological drought, cascading hazards and impacts, and measure of drought extent.

Earthquake hazard profile expanded to include information about liquefaction and coseismic landslides. Information about the Portland Hills, Gales Creek, and Beaverton fault zones and Hazus®-MH event scenarios with damage data for these faults added to the hazard profile.

Flooding hazard profile expanded to include streambank and riverbed erosion and channel migration.

Volcano hazard profile streamlined to focus on volcanic ash.

Wildfire smoke impacts included in wildfire hazard profile.

Enhanced Fujita scale added to illustrate extent of tornadoes in windstorm, including tornado hazard profile.

CFR 44 §201.6 Requirements §201.6(c)(2)(i): [The risk assessment shall include a] description of the type, location, and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

§201.6(c)(2)(ii): [The risk assessment shall include a] description of the jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section. This description shall include an overall summary of each hazard and its impact on the community. All plans approved after October 1, 2008, must also address NFIP [National Flood Insurance Program] insured structures that have been repetitively damaged by floods. The plan should describe vulnerability in terms of:

§201.6(c)(2)(ii)(A): The types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas.

§201.6(c)(2)(ii)(B): An estimate of the potential dollar losses to vulnerable structures identified in…this section and a description of the methodology used to prepare the estimate.

§201.6(c)(2)(ii)(C): Providing a general description of land uses and development trends within the community so that mitigation options can be considered in future land use decisions.

§201.6(d)(3): A local jurisdiction must review and revise its plan to reflect changes in development, progress in local mitigation efforts, and changes in priorities, and resubmit it for approval within 5 years in order to continue to be eligible for mitigation project grant funding.

Section 2: Hazard Identification and Risk Assessment 8

2.1. Risk Assessment Overview

Completing a natural hazard mitigation risk assessment allows planning participants to identify and characterize hazards that can impact them and determine what populations, built environment infrastructure, and systems are most vulnerable to each hazard. The risk assessment provides the factual basis for the mitigation strategy, including the mitigation action items, identified by each plan participant that will reduce losses from identified hazards. The assessment process consisted of three phases conducted sequentially, as each phase builds on data from prior phases.

Phase 1: Phase 1 includes identification of natural hazards that can impact the jurisdiction. This includes an evaluation of potential hazard impacts, including type, location, and extent.

Phase 2: Phase 2 includes identification of important community assets and system vulnerabilities. Example vulnerabilities include populations, economies, existing and future structures, agriculture land and property, critical facilities and infrastructure, natural environment, and changes due to climate change.

Phase 3: Phase 3 includes evaluation of the extent to which the identified hazards overlap with, or impact, the important assets identified by the community.

Each hazard profile in this section contains an analysis of hazard characteristics, hazard history, probability of future events, vulnerability assessment, and a Hazard Risk Score Summary.

This risk assessment applies to all plan participants. Relevant participant-specific risk information is in the participant annexes. This section supports the Oregon Statewide Planning Goal 7, Areas Subject to Natural Disasters and Hazards by evaluating the risk to people and property from natural hazards.

The information presented below, along with information presented in Volume III, Appendix A: Planning Area Profile, is used to inform the risk reduction actions identified in Volume I, Section 3: Mitigation Strategy.

2.2. Hazard Analysis Methodology

OEM created a hazard analysis methodology to examine hazard vulnerability and probability by collecting information about the four rating criteria of history, vulnerability, maximum threat, and probability for each hazard that impacts the communities in the planning area.

The 2017 NHMP used the OEM methodology, and for this 2023 update, the Steering Committee chose to use this methodology again to provide consistency and continuity from plan to plan. The vast majority of local NHMPs and the Oregon NHMP use this methodology, which allows comparison of the same hazard across jurisdictions statewide. This methodology does not compare hazards to each other or rank hazards against one another. Instead, this process provides a sense of hazard priorities or relative risk and allows comparison of the same hazard across participants. It provides planning participants with a sense of hazard priorities, or relative risk. By doing this analysis, mitigation can focus on the greatest risk.

While hazards occur together or as a consequence of others (e.g., dam failure may cause flooding and earthquakes may cause landslides), participants considered hazards as a singular event for the purposes of rating.

This hazard analysis methodology can:

Help establish priorities for planning, capability development, and hazard mitigation;

Serve as a tool in the identification of hazard mitigation measures;

Be one tool in conducting a hazard-based needs analysis;

Serve to educate the public and public officials about hazards and vulnerabilities; and

Section 2: Hazard Identification and Risk Assessment 9

Help communities make objective judgments about acceptable risk.

Each of the hazards examined by this analysis was scored using a formula that incorporates the four rating criteria, a weight factor, and three levels of severity: low, medium, and high. For every hazard, scores for the four rating criteria are determined by multiplying each criterion’s severity rating by its weight factor. The rating criteria scores for the hazard are then summed to provide a total score for that hazard.

The methodology produces scores that range from 24 (lowest possible) to 240 (highest possible).

Vulnerability and probability are the two key components of the methodology. Vulnerability examines both typical and maximum credible events and accounts for approximately 60% of the total score. Probability endeavors to reflect how physical changes in the jurisdiction and scientific research modify the historical record for each hazard and accounts for approximately 40% of the total score.

Definitions and values for the ratings and severity criteria and weight factors are explained below.

2.2.1. Severity Ratings

Severity ratings are applied to the four categories of history, vulnerability, maximum threat, and probability. The severity rating scales are unique to each category and are provided below.

Low: Choose the most appropriate number between 1 and 3 points.

Medium: Choose the most appropriate number between 4 and 7 points.

High: Choose the most appropriate number between 8 and 10 points.

2.2.2. History

History is the record of previous occurrences and has a weight factor of two. Events to include in assessing the history of a hazard are events for which the following types of activities were required:

The emergency operations center (EOC) or alternate EOC was activated.

Three or more emergency operations plan functions were implemented.

An extraordinary multijurisdictional response was required.

A local emergency was declared.

A severity rating is applied based on the following:

Low: 0–1 event in the past 100 years scores between 1 and 3 points.

Medium: 2–3 events in the past 100 years scores between 4 and 7 points.

High: 2–3 events in the past 100 years scores between 8 and 10 points.

2.2.3. Vulnerability

Vulnerability is the percentage of population and property likely to be affected under an average occurrence of the hazard. It has a weight factor of five. A severity rating is applied based on the following:

Low: < 1% affected scores between 1 and 3 points.

Medium: 1% to 10% affected scores between 4 and 7 points.

High: > 10% affected scores between 8 and 10 points.

Section 2: Hazard Identification and Risk Assessment 10

2.2.4. Maximum Threat

Maximum threat is the highest percentage of population and property that could be impacted under a worst-case scenario. It has a weight factor of 10. A severity rating is applied based on the following:

Low: < 5% affected scores between 1 and 3 points.

Medium: 5% to 25% affected scores between 4 and 7 points.

High: > 25% affected scores between 8 and 10 points.

2.2.5. Probability

Probability is the likelihood of future occurrence within a specified period of time and has a weight factor of seven. A severity rating is applied based on the following:

Low: One incident likely within 75 to 100 years scores between 1 and 3 points.

Medium: One incident likely within 35 to 75 years scores between 4 and 7 points.

High: One incident likely within 10 to 35 years scores between 8 and 10 points.

2.3. Hazards Identified

Through an assessment of previous federally declared disasters in Washington County, historical events and potential events in the County, and a review of available local mitigation action plans, the NHMP Steering Committee determined this plan will address the risks associated with the following 10 natural hazards:

Dam failure6

Drought

Earthquake

Extreme heat6

Flooding

Landslide

Volcanic ash

Wildland fire

Windstorm, including tornado

Winter storm

Summary information and risk assessments for each of these hazards is presented in Volume I, Section

2.7. Specific hazard risk and vulnerability information unique to each participant is presented in the participant annexes. These hazards are shown in alphabetical order and do not represent the probability, vulnerability, or hazard risk rank identified during the planning process.

The timeframe of the data collected during the planning process varied for planning participants depending on their previous NHMP participation and is reflected in Table 4 below.

6 New hazard for the 2023 NHMP update

Section 2: Hazard Identification and Risk Assessment 11

Table 4: Timeframe of Data Collected for Planning Participants

Participant Timeframe of Data Collected

From To

Washington County and the cities of Tigard and Hillsboro 11/1/2016 2/22/2022 City of Beaverton 1/1/2020 2/22/2022 Cities of Cornelius and Forest Grove 9/1/2011 2/22/2022 All other participants As far back as was available 2/22/2022

The timeframe for county-level data and information, including disaster declarations, demographics, and hazard event history, is from November 1, 2016 to February 22, 2022.

2.4. Disaster Declaration History

Since the adoption of the most recent NHMP, Washington County has been a part of four federal disaster declarations, eight Oregon disaster declarations, and two local disaster declarations. A review of federal and local disaster declarations and emergency executive orders issued by the Oregon governor since November 1, 2016, shows that wildfire, winter storm, and extreme heat events are the main hazards that significantly impacted the County.

Table 5: Federal Disaster Declarations Including Washington County Since November 1, 20167

Declaration Number

Declaration Date

Incident Period Incident Individual

Assistance Public

Assistance Categories* From To

Major Federal Disaster Declarations (DR) Including Washington County Since November 1, 2016

DR-4562 9/15/2020 9/7/2020 11/3/2020 Wildfire and Straight-line Winds No B

Federal Fire Management Assistance Declarations (FM) Including Washington County Since November 1, 2016

FM-5371 9/10/2020 9/8/2020 9/15/2020 Wildfire None B FM-5358 9/8/2020 9/8/2020 9/14/2020 Wildfire None B

Federal Emergency Declarations (EM) Including Washington County Since November 1, 2016 EM-3542 9/10/2020 9/8/2020 9/15/2020 Wildfires None B

* Eligible work in Public Assistance Category B is emergency protective measures that must be completed within six months. Eligible work must be required as a result of the declared incident, be located in the designated area, be the legal responsibility of the applicant, and be undertaken at a reasonable cost.

7 Federal Emergency Management Agency. (2022). Declared Disasters. https://www.fema.gov/disaster/declarations https://www.fema.gov/disaster/declarations

Section 2: Hazard Identification and Risk Assessment 12

Table 6: Governor Executive Orders Declaring State of Emergency Including Washington County Since November 1, 20168

Declaration Number

Declaration Date(s)

Incident Period Incident Individual

Assistance Public

Assistance From To

EO-21-37 12/23/2021 12/23/2021 1/3/2022 Severe Winter Storm Statewide No EO-21-27 8/10/2021 8/10/2021 8/20/2021 Extreme Heat Statewide No EO-21-26 7/29/2021 7/29/2021 8/5/2021 Extreme Heat No No EO-21-02 2/13/2021 2/11/2021 2/18/2021 Severe Winter Storm, High Winds, Flooding, and Landslides

No No

EO-20-43 9/14/2020 9/8/2020 9/14/2020 Invocation of Emergency Conflagration Act for the Powerline Fire

No No

EO-20-41 9/9/2020 9/8/2020 11/1/2020 Invocation of Emergency Conflagration Act

Statewide No

EO-17-06 4/13/2017 1/11/2017 3/20/2017 Severe Winter Storm, High Winds, Flooding, and Landslides

No No

EO-17-02 4/13/2017 1/11/2017 2/1/2017 Severe Winter Storm, High Winds, Flooding, and Landslides

Statewide No

Table 7: Local Disaster Declarations and Resolutions in Washington County Since November 1, 20169

Participants Declaration Date

Incident Period Incident

From To

Washington County

2/13/2021 2/12/2021 2/13/2021 Severe Winter Storm

Washington County

9/11/2020 9/8/2020 9/29/2020 Two concurrent wildfires: Powerline–Henry Hagg Lake– Cherry Grove wildfire (Powerline wildfire) and Chehalem Mountain–Bald Peak wildfire

8 Office of Oregon Governor. (n.d.). Executive Orders. https://www.oregon.gov/gov/Pages/executive-orders.aspx 9 2023 NHMP Participant Planning Documentation https://www.oregon.gov/gov/Pages/executive-orders.aspx

Section 2: Hazard Identification and Risk Assessment 13

2.5. Vulnerability Assessments

A detailed community profile, which includes information on the vulnerabilities below, is in Volume III, Appendix A. Participant-specific information and vulnerabilities are identified in the annexes, as appropriate, and include:

Populations

Economies

Structures (existing and future)

Improved property

Critical facilities and infrastructure

Natural environment

Changes in development for participants with previous mitigation plans are described in participant annexes, as applicable. This includes information about increases and decreases in vulnerability and changes in priorities, as appropriate.

2.6. Summary of Participant Hazard Risk Scores

Based on the risk assessment methodology outlined in Section 2.2, each NHMP participant assigned a risk score to each of the hazards identified in this plan. Each of the hazards examined by this analysis was scored using a formula that incorporates the four rating criteria, a weight factor, and three levels of severity: low, medium, and high. The score range for this methodology is 24 (lowest possible) to 240 (highest possible).

Section 2: Hazard Identification and Risk Assessment 14

Table 8: Summary of Participant Hazard Risk Scores

Hazard Risk Score

Participant Dam Failure Drought

Earthquake:

Cascadia

(3–5-minute event)

Earthquake:

Crustal (1-minute event)

Extreme Heat Flooding Landslide Volcanic

Ash Wildland

Fire Windstorm, Including Tornado

Winter Storm

City of Beaverton

– 198 196 196 212 188 86 178 – 208 203

City of Cornelius

83 186 201 201 148 48 118 99 240 240 240

City of Forest Grove

83 186 201 201 148 48 118 99 240 240 240

City of Hillsboro

81 184 201 201 179 159 34 126 177 205 205

City of North Plains

56 170 201 71 177 181 24 124 201 132 187

City of Sherwood

74 175 186 158 162 79 61 119 142 178 208

City of Tigard 95 167 203 203 162 162 73 137 168 205 205

Clean Water Services

78 165 148 155 152 189 96 86 127 147 142

Tualatin Hills Park & Recreation District

24 166 161 161 199 143 72 152 143 198 208

Tualatin Valley Water District

133 186 201 159 177 67 88 119 161 169 206

Washington County

83 186 201 201 177 173 102 124 191 132 211

Section 2: Hazard Identification and Risk Assessment 15

2.7. Hazard Profiles

The following natural hazard profiles are listed in alphabetical order and do not represent their rank, as each jurisdiction prioritized the hazards independently. The information provided in this section reflects the impact of the hazards on all of Washington County, not solely the participating jurisdictions and special districts.

Each profile provides a hazard description, significant events since the adoption of the 2017 NHMP, if applicable, and potential impacts and vulnerabilities. The potential impacts for each hazard are presented in the same order, as applicable: populations, economies, structures, improved property, critical facilities and infrastructure, historical properties and cultural resources, and natural environments.

The timeframe of data collected during the planning process for Washington County was November 1, 2016 to February 22, 2022.

Participant-specific hazard and vulnerability information is identified in the annexes, as appropriate.

Section 2.7.1: Dam Failure 16

2.7.1. Dam Failure

Significant Changes Created standalone hazard profile.

Additional information on vulnerabilities and how climate change may impact the frequency and severity of dam failure added.

2.7.1.1. Characteristics

Dams protect water resources used for drinking, agriculture, and recreation and protect downstream development from inundation. Dams may be multi-functional, serving two or more of these purposes.

Human-made dams may be classified according to the type of construction material used, construction methods, the slope or cross-section of the dam, the way the dam resists the forces of the water pressure…