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Issaquah Creek Mitigation Project

Issaquah Creek Mitigation Project

Mitigation Reserves Program

April 2022:


Project Description

Located in the Sammamish River Service Area, the Middle Issaquah Creek Natural Area consists of 41.3 acres of public land along Issaquah Creek. Within the Middle Issaquah Creek Natural Area, the Issaquah Creek mitigation project will remove existing fill, create wetlands, place large wood and wildlife trees, and restore native vegetation to create a riverine wetland that improves water quality and hydrology, and provides habitat for fish and wildlife.

December 2019:



This project will fulfill in-lieu fee mitigation credit obligations for the Mitigation Reserves Program, which is providing compensatory mitigation for unavoidable wetland and aquatic area impacts associated with development in the Sammamish Service Area. By creating and enhancing wetlands, the project helps to protect and improve water quality, provide habitat, store floodwaters, and maintain water flow during droughts. Restoring these ecosystem services will improve the Middle Issaquah Creek Natural Area, and benefit area residents.

Vicinity Maps


Issaquah Creek Mitigation Project Vicinity Map  

JPEG (738 KB)

Issaquah Creek Area Existing Public Lands

JPEG (603 KB)

Diagram of Mitigation Project

Issaquah Creek Mitigation Project Mitigation Credit Areas and Perimeter Protection 

JPEG (1,707 KB)

Pre-Construction Aerial



Project Schedule

Issaquah Creek Mitigation Project schedule overview
Alternatives analysis complete                  July 2017
30% design complete February 2018
60% design complete June 2018
100% design complete October 2018
Notice to Proceed March 2019
Implementation 2019
Monitoring 2020-2030


Project Documents

Determination of Non-Significance PDF (146 KB) 

Environmental Checklist PDF (1.76 MB)

For questions about King County's Mitigation Reserves Program, please contact program staff.