Tuolumne River Bobcat Flat Salmonid Habitat Restoration

(Photo © Tuolumne River Conservancy, all rights reserved)

The California Department of Fish and Wildlife awarded the Tuolumne River Conservancy with Proposition 1 funds to implement the Duck Slough Restoration Project, which built a new side-channel to improve habitat for fish and wildlife. The Duck Slough Restoration Project is part of the larger Bobcat Flat Restoration Project located along the lower Tuolumne River. The Bobcat Flat Restoration Project restored instream and floodplain habitat for Chinook salmon and steelhead trout.

• Project Proponent: Tuolumne River Conservancy
• Focus Habitat/Species: Chinook salmon and steelhead trout off-channel habitat
• CDFW Grant Support: $453,618
• Location: Tuolumne River, Stanislaus County, California
• Scale: 0.5 acres of habitat/0.76 miles of channel
• Timing: Constructed September 2016
• Funding Source: Proposition 1
• Priority: Protect and Restore Anadromous Fish Habitat

Background I: Lower Tuolumne River

The lower Tuolumne River was heavily impacted by gold mining practices that used a huge floating dredger. Dredger operations removed gravel from the river bottom and deposited the gravel on the river banks. This left much of the lower river’s floodplain covered with gravel tailings.

Gravel tailing areas are rocky and do not support very much plant growth. In addition, dredger operations left hard bedrock or sand on the river floor. The removal of gravel from the river destroyed the spawning areas (where fish release eggs) of Chinook salmon and steelhead trout, which lay eggs in gravel on the river bottom

 Background II: Bobcat Flat Early Phases

The early phases of the Bobcat Flat Restoration Project restored floodplain and stream habitat along the lower Tuolumne River. Phase 1 restoration restored streamside habitat, known as the riparian area, and improved floodplain function and connection to the Tuolumne River. 

Phase 2 of restoration began in 2011 and created new stream riffles, increased the floodplain and river connection, and restored the riparian area. Early phases were funded by the USFWS’s Anadromous Fish Restoration Program, the California Department of Water Resources, the City and County of San Francisco, and the Tuolumne River Conservancy. 

 Project: Duck Slough Restoration - Before and After

In 2016, CDFW awarded Proposition 1 funds for the Duck Slough Restoration Project. 

This project turned a gravel tailing area in a dead-end slough that was covered in invasive aquatic weeds ...

... into a healthy, streamside channel connected to the Tuolumne River.

The Project

created winter habitat for young Chinook Salmon and steelhead,

established new habitat for out-migrating salmonids during spring dam releases,

reduced habitat for non-native fish, and

removed the invasive plant water hyacinth (Eichhornia crassipes).

Project: Duck Slough Restoration

The spawning gravels were placed in select areas in the new side channel to create pool-riffle habitat, which is ideal for young Chinook salmon and steelhead to spawn and grow before swimming out to the ocean.  These gravels provide shelter for young fish and for insects, which are the main food of these fish.

The Duck Slough Restoration Project fits into plans for the overall watershed by allowing flooding flows that are consistent with the Lower Tuolumne River Corridor Habitat Restoration Plan goals.

 EcoAtlas  contains further project information. 

For more project information please contact:  tuolumneriverconservancy.org 

To see other Project Highlight StoryMaps like this one, see:  https://www.wildlife.ca.gov/Conservation/Watersheds/Project-Highlights 

For Information on Proposition 1/68 Projects, please see:  https://www.wildlife.ca.gov/Conservation/Watersheds/Restoration-Grants/Projects 

For further information, please contact:  WatershedGrants@wildlife.ca.gov