Translate
Issaquah Creek Capital Investment Strategy
Learn about the Issaquah Creek Capital Investment Strategy (CIS), a plan for investments in projects and programs that reduce flood risk in the Issaquah Creek Basin while providing multiple social and environmental benefits for communities. Public input will help shape this plan; sign up for updates.
Project overview
The Issaquah Creek basin is home to a unique mix of diverse natural resources, striking landscapes, and vibrant communities. The basin covers about 52 square miles of central King County, flowing north from its headwaters in Tiger Mountain and Taylor Mountain and draining into Lake Sammamish.
Along the way, Issaquah Creek flows through forest and farmlands, state parks and conservation areas, vibrant small towns and communities, and the fast-growing City of Issaquah. The basin is recognized as a salmon resource with some of the highest quality habitat in area.
Major flooding along Issaquah Creek in February 2020 caused significant damage to nearby homes and public infrastructure. In response, the King County Flood Control District (the District), together with King County as service provider, is working to improve flood resilience with new technical studies, infrastructure projects, and flood facility repairs.
In tandem with these efforts, the District authorized the development of a Capital Investment Strategy for Issaquah Creek and two of its tributaries where flood facilities are located. The King County Water and Land Resources Division will be implementing the Capital Investment Strategy (CIS) as service provider to the District.
The Issaquah Creek CIS will be a plan for investments in projects and programs that reduce flood risk in the Issaquah Creek Basin while providing multiple social and environmental benefits for communities. The CIS will be developed through a robust engagement process that aims to understand the specific needs and values of communities living, working, and utilizing Issaquah Creek.
The CIS will build on previous and ongoing studies in the Issaquah Creek basin authorized by the District. These include the:
- Issaquah Creek Flood Study
- Issaquah Creek Channel Migration Zone Study
- East Fork and Mainstem Stream Evaluations (authorized through the Flood Reduction Grant Fund to the City of Issaquah).
Did you know
Issaquah Creek is home to the Issaquah State Salmon Hatchery. The hatchery is an important part of state fisheries practices and maintaining treaty-reserved tribal fishing rights. You can visit the Issaquah State Salmon Hatchery virtually or in-person to learn more about salmon journeys and clean watersheds.
Study area
The Issaquah Creek CIS is focused on the 100-year floodplain of Issaquah Creek, specifically targeting the 41 river facilities (levees and revetments), managed by King County, that are located along Issaquah Creek and portions of Holder and Fifteen Mile Creek. The river facilities are shown in pink in the map below.
Key Terms
What is a Capital Investment Strategy (CIS)?
A plan for how and where investments in flood risk reduction will happen in a river basin.
What is a river facility?
Usually a levee or revetment.
What is a revetment?
A revetment is a structure built along a riverbank to prevent erosion. Revetments are usually built with rocks, wood, and other materials. Native plants are added to the riverbank to improve stability and provide habitat for fish and wildlife.
What is a levee?
A levee is a raised structure built along a riverbank to contain, control, or divert the flow of water and protect the land along the river from temporary flooding. A levee is usually made of earth and runs parallel to the course of a river.
What is channel migration?
The natural movement of a river laterally (from side to side) across its floodplain over time.
Project Goals and Objectives
The goal of the Issaquah Creek CIS is to reduce flood risks in the Issaquah Creek basin through an integrated floodplain management approach and consideration of multiple benefits.
The project objectives are to:
- Provide information and enhance programs that will help communities become aware of flood risks and will help communities prepare for and respond to floods.
- Develop a CIS to prioritize projects and programs that reduce flood risk in the Issaquah Creek Basin while providing multiple social and environmental benefits for communities.
- Identify potential partnerships and funding opportunities through public engagement and collaboration with those most at risk and vulnerable to floods.
Project schedule
| Activity |
Date |
|---|---|
| Project pre-planning |
2024 |
| Data gathering and public engagement |
2024 to 2025 |
| District review and approval phase | 2025 |
| CIS Drafted |
2025 to 2026 |
| Approved CIS – project completed |
2026 |
Participate in the project!
There will be multiple opportunities for sharing input as the Issaquah Creek CIS is being developed. These will include public meetings, comment periods, focus groups, online engagement hubs, and CIS project team attendance at community events such as festivals, farmers markets, and holiday fairs.
Opportunities to participate will be posted here when they are available. You can also sign-up for email alerts about updates related to Issaquah Creek floods and flood-related work at the link above.