This project removed two fish passage barriers from Pescadero Creek at Memorial County Park near Loma Mar in San Mateo County — a remnant dam and a concrete vehicle ford — replacing them with a restored natural creek bed and v-notched weirs with arched culverts allowing passage across a wider range of flows. The project opened 62.3 miles of unimpeded spawning and rearing habitat, a high-priority recovery action for nearly extirpated Central California Coast coho salmon and steelhead trout.
Location: Pescadero Creek runs through Memorial County Park, draining an 80 square mile watershed from the Santa Cruz Mountains, before emptying into Pescadero Marsh and the Pacific Ocean. Memorial County Park is located near Loma Mar in San Mateo County, California. Pescadero Creek is the only independent coho recovery watershed in San Mateo County.
Historical Presence of Anadromous Fish: Historically, there was an abundance of coho salmon and steelhead trout in Pescadero Creek. With the exception of a few juvenile coho observed in 1999, coho are believed to be nearly extirpated from the Pescadero system. In 2003, 17,000 hatchery-raised coho smolts were released into Pescadero Creek, but adult coho have only been observed at a few locations over the subsequent decade.
Project Lead Organization: San Mateo Resource Conservation District (San Mateo RCD)
Project Partners: San Mateo County Parks Department; California Department of Fish and Wildlife (Fisheries Restoration Grant Program); NOAA Fisheries; California Coastal Conservancy (via IWRP); San Mateo County Parks Foundation
Funding from the California Fish Passage Forum: $67,243
Project Description: The two barriers were remnants a dam built to create a swimming hole and a concrete span providing access to a popular campground. The dam was demolished and the natural creek bed was restored at that site. The vehicle ford was replaced with v-notched weirs and pre-cast arched culverts that allow freer fish passage at a wider range of water levels, especially for juveniles during low flows. Construction had to occur within a short timeframe due to the presence of endangered marbled murrelet nests in nearby old-growth redwoods and the need to keep the park open during the popular summer season. The project was identified as a top priority in multiple state and federal coho and steelhead recovery plans.
Expected Completion: Fall 2015, with post-construction monitoring planned for Winter 2015-2016.
Project Effectiveness: The RCD and San Mateo County Parks removed the final two human-made barriers to fish passage in Pescadero Creek, opening up 62.3 miles of unimpeded access to spawning and rearing habitat for coho salmon and steelhead trout. After just one winter, immediate benefits included a free-flowing stream with unimpeded fish passage, plus the transference of stored sediment, gravel, and cobble to downstream areas, creating more complex habitat.
