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King County Flood Management Plan

The Flood Management Plan guides how King County manages flood risks along our rivers, creeks, and shorelines. The new plan is in the final stages of development.

Public involvement opportunities

Draft Flood Plan public comment period: Jan. 31 – March 15, 2024, 5 p.m. (PT)

King County is in the final stages of updating its Flood Management Plan and offering another opportunity to help shape a strategy that will better prepare the region for more frequent, severe flooding expected to occur due to climate change. Visit the King County Engagement Hub to see a synopsis of the recommendations being proposed based on community and partner input.

Comments can be submitted by mail, email or using the online form on the King County Engagement Hub.

Email: jason.wilkinson@kingcounty.gov

Mail: 
King County Water and Land Resources Division
Attn: Jason Wilkinson
201 S. Jackson Street, Rm 5600
Seattle, WA 98104

Public meetings

During the public comment period, King County is hosting two online public meetings to share information about the draft Flood Plan and to hear from you. Follow the link for your preferred date below and register today.

Both meetings will be held virtually using Zoom. King County staff will share input the public and partners offered during the planning process and will highlight how that information informed the draft Flood Plan. You will also be able to share your comments on the draft Flood Plan, which will inform development of the final plan. The meetings will be recorded and posted online for those who are interested but unable to attend.

SEPA review comment period: Feb. 16 – March 18, 2024, 5 p.m. (PT)

The draft EIS is available for public review and comment. This formal comment opportunity requests comments on the adequacy of environmental analysis. Is anything in the draft inaccurate? Were any environmental impacts or potential mitigation measures missed in the analysis? Where negative impacts are identified, should measures beyond those listed in the draft be considered?

Comments can be submitted by mail, email or using the online form on the King County Engagement Hub.

Email: jason.wilkinson@kingcounty.gov

Mail: 
King County Water and Land Resources Division
Attn: Jason Wilkinson
201 S. Jackson Street, Rm 5600
Seattle, WA 98104

State Environmental Policy Act process

An important part of our process to update the Flood Management Plan is to prepare an environmental impact statement (EIS). An EIS is a document that describes proposed actions and how they would affect the environment and people. Through the EIS process, King County will identify and analyze potential impacts of the plan on threatened or endangered species, water quality, historical and cultural resources, transportation, and more.

King County will explore the impacts of two scenarios, called “alternatives,” in the EIS. As a standard part of the EIS process, a “no action alternative” is considered. The analysis will consider the impacts of not adopting the new flood plan (the no action alternative) and continuing to use the 2006 and 2013 flood plans to guide floodplain management policy and activities and will also evaluate the impacts associated with adopting the new flood plan.

The County’s current flood plan focuses on flooding and erosion hazards on major rivers and streams like the Snoqualmie and Cedar rivers and Issaquah Creek. The updated flood plan proposes to address flooding more broadly on smaller streams and tributaries, lakes, and in urbans and coastal areas. Public comments from the EIS scoping period confirmed this broader scope has the potential to result in better outcomes for King County communities. 

Scoping period (completed in 2022)

The scoping period is a formal opportunity for public input. We invited the public, tribal governments, and local, state, and federal agencies to comment on the range of alternatives, areas of impact, and possible mitigation measures that should be evaluated within the EIS.

A 30-day comment period was held from Monday, Nov. 7 to Friday, Dec. 9, 2022. The submitted comments provided valuable information about topics to consider in evaluating potential environmental impacts. We also received comments that are not applicable to the EIS analysis but are relevant to the flood plan itself, and those comments will be considered as part of plan development.

Review the King County Flood Plan Environmental Impact Statement (EIS) Scoping Summary (May 2023), (PDF, 190 KB)

About the flood plan update

As our most common natural disaster, flooding is part of life in King County. The plan will set floodplain management policy for unincorporated King County and could inform flood management actions by cities, the King County Flood Control District, and other floodplain partners.

Our core values in developing the flood plan are:

  • To stay community-centered.
  • Embrace transparency and openness.
  • Work with local partners.
  • Strive for full accessibility.
  • Have communities that are often left out of flood risk reduction conversations at the table. 
People work to assess damage to State Route 202 caused by the flooding of the Snoqualmie River in 2009.

Why is King County updating the flood plan?

Rivers and streams are alive—they change over time. King County last updated the flood plan in 2013. Since then, nearly 10 seasons of flooding have changed how our rivers look and function. Our population has grown, and we’ve added more homes and businesses to the landscape. How we develop land, manage waste, accommodate traffic, grow food, and recreate affects our rivers and coastal areas.

How will this flood plan be different?

To create a flood resilient future, the plan must represent the diverse perspectives of our community. Due to unjust historical practices, some communities are more at risk of flooding. Some people are less able to prepare or recover from flood disasters. Understanding what all communities need and their proposed solutions is King County’s priority.

Past plans have focused on flooding along King County’s major rivers. This plan will capture a broader range of flood hazards that affect people. It will include coastal flood hazards and sea level rise, small stream flooding, and urban flooding.

The updated plan will look for ways that we can reduce flood risks while delivering other community benefits. How can our projects and programs support farming or create new jobs? Improve salmon habitat and provide recreational areas? What's most important to you and what does your community need?

Partner Planning Committee

The Partner Planning Committee is one avenue for gathering public input on the flood plan. Learn more about the purpose of the committee and upcoming committee meetings on the Partner Planning Committee webpage.

Coastal flooding on Vashon Island in 2021.

Past flood plans

The most recent flood plan was completed in 2006 and adopted by King County Council in January 2007. The flood plan was last updated in 2013 and adopted by King County Council with the passage of Ordinance No. 2013-0419.

Download the 2006 flood plan and 2013 flood plan update. These reports are provided in Adobe Acrobat .pdf format.

2006 King County Flood Hazard Management Plan (16.6 MB)

2013 King County Flood Hazard Management Plan Update and Progress Report (4 MB)

Printed copies of the 2006 flood plan and 2013 flood plan update are available at the following King County libraries:

  • Auburn Library
  • Bellevue Regional Library
  • Bothell Regional Library
  • Carnation Library
  • Duvall Library
  • Fairwood Library
  • Fall City Library
  • Issaquah Library
  • Kent Library
  • Maple Valley Library
  • Muckleshoot Library
  • North Bend Library
  • Redmond Regional Library
  • Skykomish Library
  • Snoqualmie Library
  • Tukwila Library 
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