This project replaced a severely undersized, failing private road culvert on Upper Green Valley Creek — a Russian River tributary in Sonoma County — with a 15-foot bottomless arch culvert and a 157-foot step-pool roughened channel with boulder weirs for grade control. The culvert had blocked coho access under all flow conditions. The project opened 0.9 miles of spawning and rearing habitat, and post-construction surveys detected 136 steelhead young-of-year upstream of the site, benefiting federally endangered Central California Coast coho salmon and threatened steelhead.
Location: Upper Green Valley Creek, a tributary to the Russian River, Sonoma County, CA. The project site is located approximately 0.9 miles above the confluence with lower Green Valley Creek, a major tributary to the lower Russian River.
Historical Fish Presence: Central California Coast (CCC) coho salmon (Oncorhynchus kisutch), listed as endangered at both state and federal levels, and North Coast Diversity Stratum steelhead trout (Oncorhynchus mykiss), listed as threatened. Green Valley Creek was one of only three Russian River tributaries where coho were recorded in the early 2000s, making it a focus watershed for CDFW’s coho recovery program and the Russian River Coho Salmon Captive Broodstock Program, which has been stocking juvenile coho into the creek since 2006. The Guerneville hydrologic subarea is ranked at the highest level (5) for restoration potential within the CCC Coho ESU.
Project Lead: Gold Ridge Resource Conservation District (GRRCD)
Project Partners: Stetson Engineers; Point Blue Conservation Science; McCullough Construction. Funding support from California Department of Fish and Wildlife’s Fisheries Restoration Grant Program (FRGP), and the U.S. Fish and Wildlife Service (Grant No. 18-25G).
CFPF Funding: $30,089.09
Project Description: An undersized, rusted, and failing private road culvert with an inlet invert sitting 11.5 feet above the outlet pool was serving as de facto grade control for an actively incising reach of upper Green Valley Creek and blocking coho passage under all flow conditions. Its imminent failure threatened to further disconnect the floodplain above and worsen fine sediment loading downstream. The project replaced the culvert with a 15ft x 7.75ft bottomless arch culvert, constructed a 157-foot step-pool roughened channel through the crossing, and installed two series of boulder weirs for grade control on either end. Riparian revegetation of over 650 native plants across 1.1 acres was completed and is required to reach 80% survival over three years. The project opened 0.9 miles (4,810 feet) of rearing and spawning habitat previously inaccessible to coho under any flow conditions.
Expected Completion: Fall 2017.
Project Effectiveness: Pre-construction surveys detected 2 coho and 13 resident rainbow trout/steelhead at the project site, along with sculpin, stickleback, California freshwater shrimp, lamprey, and sunfish. No spawners or carcasses were detected during pre-construction spawner surveys. Post-construction snorkeling surveys detected 136 steelhead young-of-year upstream of the project site, indicating successful upstream passage following construction. No coho young-of-year were detected, though coho recovery in the watershed is a long-term goal dependent on ongoing broodstock reintroduction and downstream barrier removal efforts.
