Boise Creek Mitigation Project

Project description

The Boise Creek Mitigation Project is located on a 4.5-acre portion of the Middle Boise Creek Natural Area on the left bank of Boise Creek downstream from 284^th Ave SE. The Boise Creek Mitigation Project will create wetland and aquatic habitat while preserving native riparian buffers. Construction begins in 2024 and the completed project will create 2 acres of new wetland and aquatic area. The Boise Creek Mitigation Project will compensate for unavoidable permitted impacts to wetlands and aquatic resources in Water Resource Inventory Area (WRIA) 10.

Background

Boise Creek is extremely important to the Puyallup/White River Watershed because it provides spawning and rearing habitat for Chinook salmon (spring, fall runs) and steelhead trout. Coho, pink, and chum salmon, and cutthroat trout are also present in Boise Creek. Boise Creek is degraded due to past land use activities and water temperatures in Boise Creek consistently exceed state standards for salmon spawning and incubation. There is a significant lack of woody vegetation, and consequently, shade to the creek.

Boise Creek is identified in the Salmon Habitat Protection and Restoration Strategy for Puyallup and Chambers Watersheds as a high priority tributary for restoration and protection of natural geomorphic processes and riparian function. King County has successfully implemented three salmon restoration projects on Boise Creek downstream of the Boise Creek Mitigation Project. The Boise Creek Mitigation Project will complement these successful projects and add rearing and refuge habitat for salmon further upstream. The project will protect riparian habitat and is expected to improve water quality, while adding needed salmonid habitat on Boise Creek. Wetlands will be established with large wood and diverse native vegetation. The Boise Creek Mitigation Project will provide mitigation credits for King County’s Mitigation Reserves Program.