Category: 2017

Cooper Mill Creek Fish Passage Improvement Project Designs

This project funded site characterization and engineering design work for two legacy fish passage barriers on lower Cooper Mill Creek, a tributary to Yager Creek within the Van Duzen River basin in Humboldt County — a boulder step-weir complex at the creek mouth and a concrete sill approximately 0.5 miles upstream. Hydraulic modeling confirmed both structures block adult and juvenile salmonids at most flows. The designs will support future physical removal of barriers to coho salmon, Chinook salmon, and steelhead in a historically productive watershed.
Upper Green Valley Creek Fish Passage Project

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.
Pennington Creek Steelhead Barrier Removal Project

This project removed a 1920s-era concrete diversion weir and ineffective fish ladder on Pennington Creek at the Rancho El Chorro Outdoor School in San Luis Obispo County, replacing approximately 160 linear feet of channel with engineered step pools. A new fish screen was installed at the diversion intake with a minimum bypass flow protective of steelhead critical habitat. The project opened 2.3 miles of perennial upstream habitat to federally threatened South-Central California Coast steelhead, with juveniles observed using the restored channel just six days after construction ended.