DESCRIPTION
Mid-Columbia Fisheries Enhancement Group will complete final design and permitting to restore 1.24 miles of the Little Naches River. The Little Naches River has been severely altered by a variety of land use practices. Within the project reach, Forest Road 1900 confines the river along its right bank and the historic removal of log jams has resulted in lack of instream wood. A 700 ft levee was constructed along the left bank, which is paralleled by a 600 ft levee on the right bank. The streambed was bulldozed in an attempt to access the water table that lowered following excavation of a borrow pit adjacent to the stream. The combination of these actions has created fish passage issues, disconnected the river from its historic floodplain, and increased the power and transportation capacity of the Little Naches during spring runoff. Currently, the Little Naches River is inhabited by resident cutthroat and rainbow trout, spring Chinook salmon, ESA listed Mid-Columbia steelhead, and ESA listed bull trout.
The goals of this project are to:
Increase the effective floodprone width to dissipate flood energy and create more balance between scour and deposition;
Increase habitat complexity by increasing pool frequency, instream large wood density, availability of low velocity refugia, and the spatial extent of spawning habitat;
Increase the expanse of riparian vegetation; and
Maintain perennial streamflow.
Mid-Columbia Fisheries Enhancement Group completed final design and permitting to restore one mile of the Little Naches River between River Mile 3.3 and 4.3. The Little Naches River has been severely impacted by historic land use practices that have left a legacy of impacts on this system. Large wood was actively removed from the stream channel to reduce localized flooding. The stream channel was relocated for the construction of the FS 1900 road, which was built to extract timber from the watershed and provide recreation access. In the project reach, Forest Road 1900 and a 600 ft levee confine the river along its right bank, which is paralleled by a 700 ft levee along the left bank. In the early 1980's the channel bed was dug down to increase the duration of surface flow during low flow periods of the year. These activities have reduced in-stream channel complexity, increased the power of high flows, caused channel incision, and restricted the river from accessing the historic floodplain (Sondossi, 2017). These historic impacts continue to impair natural processes and impede the recovery of spring Chinook salmon, coho salmon, cutthroat trout, and threatened bull trout and steelhead populations.
The goals of this project were to complete designs for a restoration project that when constructed would:
- Remove the levees to increase the effective floodprone width to dissipate flood energy and create more balance between scour and deposition;
- Add 65 engineered log jams and additional single logs to increase habitat complexity by increasing pool frequency, instream large wood density, availability of low velocity refugia, and the spatial extent of spawning habitat;
- Increase the expanse of riparian vegetation through active planting and changes in hydrology; and
- Rebuild the streambed and activate hyporheic storage to maintain perennial streamflow.
Mid-Columbia Fisheries worked with Tetra Tech, Inc. and other partners to complete final design in the spring of 2022. All permits were secured by July, 2022. Restoration designs were implemented in the summer of 2022 and funded in part through PRISM project 22-1002 “Little Naches River Restoration, RM 3.3 to 4.3”. A cultural resources monitor observed portions of the construction activity in August, 2022, as required in the cultural resource consultation.
