DESCRIPTION
The City of Issaquah will restore in-stream and riparian habitat along approximately 1,200 feet of Issaquah Creek. The project proposes to increase the floodplain by incorporating side and backwater channels, remove existing bank armoring to increase channel habitat, place large woody debris in the main channel and backwater/side channels, remove invasive plant species and plant native trees and shrubs. Project habitat improvement actions will contribute to the formation and functioning of high-quality, low-velocity refuge habitat and cover for several species of salmonid fish across the entire range of flow stages at various life history stages. Providing such rearing and refuge habitat for juvenile Chinook salmon is the primary emphasis. Several right bank backwater and side channel areas will be excavated with wood and vegetation placed to create these quiet-water areas across essentially the full range of flows and stages. In the process of excavating these off-channel floodplain habitat areas, most of the existing rip rap stream armoring along the right (east) bank will also be removed. Clustered logs with root wads extending part way into the channel will result in localized downward scour to form pools and lower-flow, quiet-water refuge areas for fish, and at the same time provide protective cover within those habitats. The project will increase cover within those pools, and generally improve rearing habitat for juveniles and holding habitat for adults.
NOTES
Currently under private ownership, but is for sale only as the entire 12.5-acre site. Property spans from Issaquah Creek to the North Fork. Property is adjacent to City of Issaquah property. Much of the property is located in the 100 yr. floodplain, and is therefore not at high risk for development. This is both a potential Corps project as well as a potential WSDOT mitigation site ($1.1m). Acquisition will be expensive.
Issaquah Creek - Pickering Reach is located on opposite (west) bank, and a previous City restoration site is located just downstream. Site includes hardened banks and a confined channel that should be restored/revegetated. There is no LWD in this reach. It may also be possible to restore wetlands on site which could facilitate recharge of de-watered section of the North Fork.