Skip

Dam Removal in Napa County Helps Restore Fish Habitat & Riparian Corridor Health

Dam Removal in Napa County Helps Restore Fish Habitat & Riparian Corridor Health

Aerial View of the Dry Creek Fish Habitat Restoration Project and adjacent lands.
Aerial View: An aerial view shows the Dry Creek Fish Habitat Restoration Project and adjacent lands.

Hall Wines of Napa County and a committed partnership of conservation agencies have combined resources to open up 16.9 miles of high quality habitat for steelhead trout migration, spawning and rearing on an important tributary to the Napa River. Removal of the water impoundment on Dry Creek has improved the passage and water availability for federally-listed steelhead trout and improved the riparian corridor.

According to District Conservationist Phill Blake of the USDA-Natural Resources Conservation Service (NRCS), the project removed barriers to the fish as well as mitigated environmental concerns that needed to be addressed by the partnership of local, state and federal agencies.

Blake said, "The water impoundment was constructed in 1965 for vineyard frost protection. Its removal opened up a very important and historic fish spawning area for the first time in 40 years. Private landowners and public agencies with various concerns had a shared commitment and worked together to protect and conserve wildlife and the natural environment."

This seasonal water retention structure was removed because it acted as a low-flow barrier to Steelhead and Chinook salmon.
Dry Creek Before: This seasonal water retention structure, including its bridge, wing walls and sill, was removed because it acted as a low-flow barrier to Steelhead and Chinook salmon.

Beyond opening the creek for steelhead spawning, the project has improved streambank stability and the health of the riparian corridor by removing invasive plants and replanting native species. It provides vineyard protection from Pierce’s disease, releases accumulated sediments and provides a demonstration site for future fish barrier removal projects. Senior Biologist Jonathan Koehler of the Napa County Resource Conservation District (RCD) described the extent of the project.

Koehler said, "We used our habitat surveys and Friends of the Napa River snorkel counts to accurately calculate the steelhead stream mileage in the Dry Creek Watershed that benefits from the Hall dam removal project. It includes 8.8 miles of high quality rearing habitat plus some areas with isolated pools. There are 13.1 miles of potential steelhead rearing habitat, including four main tributaries: the Segassia, Wing Canyon, Montgomery and Campbell. We expect that steelhead will use 16.9 total stream miles including the main tributaries for migration, spawning and rearing. These are impressive numbers. I think we are swimming in the right direction."

After structure removal, banks were laid back and stabilized with willow brush mattress and toe rock along the north bank.
Dry Creek After: After structure removal, banks were laid back and stabilized with willow brush mattress and toe rock along the north bank. A boulder weir constructed in place of the removed sill, stabilizes the channel flow and allows for easier fish passage.

Several agencies worked together with Hall Wines on the Dry Creek project. The Napa County RCD was the lead agency for project coordination and administration. The USDA-NRCS provided engineering design and planning assistance along with $140,896 in funds from its Wildlife Habitat Incentives Program. The California Department of Fish and Game provided permit and design review assistance and $89,000 in funds from its Fisheries Restoration Program.

The San Francisco Bay Water Quality Control Board provided state bonds and funds for a feasibility study, planning and permits. The Napa County Wildlife Conservation Commission provided funds for invasive plant removal. The California Land Stewardship Institute provided guidance through its Napa Green Fish Friendly Farming program.

Future work to enhance Dry Creek includes: further instream restoration work upstream, continued removal of invasive plants and revegetation with native plants, assessment of opportunities to stabilize the headcut moving upstream from the Napa River, streamlining of the permitting program to facilitate environmentally beneficial projects, education and demonstration opportunities for future barrier removal projects.