Zanker Farm Salmonid Habitat Restoration Project

All FY16 PCSRF funds were spent within the award period (even though the project ended outside the FY16 award period). In 2023, the Zanker Phase I project (Q1940405) and the Zanker Phase II project (Q2140407) were combined into a single 100% (final) design extending along 1.6 miles of the Lower Tuolumne River. The Project will place 85,370 cubic yards of gravel as in-channel features and excavate 12.7 acres of new floodplain and side channel habitat. In-channel features include 17 new riffles and 16 new gravel bars to increase spawning habitat. Riffles were designed to either promote sediment transport and geomorphic function or for spawning and benthic macroinvertebrate production. Hydraulic modeling results showed velocity throughout the riffles falls within the range of suitable habitat for O. mykiss and Chinook Salmon. Floodplain and side channel surfaces will inundate at approximately 300 cfs, providing low velocity refuge, primary and secondary production, and cover.

The Project will result in increased rearing habitat complexity, additional food resources for juvenile salmonids and other native fish, refuge habitat from predators, and main channel spawning; which together supports increased native fish species production in the Tuolumne River. This project not only targets improved physical habitat, but also water quality benefits, in particular, improved channel temperatures. Restored side channel habitat will result in rearing space for an additional 24,500 to 898,000 juvenile salmonids ranging in size from 30 mm to 120 mm. Constructed spawning riffles will improve spawning conditions for adult salmonids.