In June 2006, the SFPUC adopted the Water Enterprise Environmental Stewardship Policy and began to integrate this policy into the planning and operation of the Bay Area’s water system infrastructure, including Hetch Hetchy Project dams and diversions in the Sierra Nevada. The policy establishes a management directive to protect and rehabilitate ecosystems affected by water system operations, within the context of meeting water supply, power generation, water quality, and existing minimum instream flow requirements. The policy further directs the nature of SFPUC instream flow releases such that they mimic, to the extent feasible, “…the variation of the seasonal hydrology (e.g., magnitude, timing, duration, and frequency) of their corresponding watersheds in order to sustain the aquatic and riparian ecosystems upon which native fish and wildlife species depend.”
Subsequent to adoption of the Environmental Stewardship Policy, the SFPUC initiated the Upper Tuolumne River Ecosystem Project with the goal of conducting a set of long-term, collaborative, science-based investigations designed to:
- Characterize historical and current river ecosystem conditions
- Assess their relationship to Hetch Hetchy Project operations
- Develop environmental flow and other recommendations for improving ecosystem conditions
Primary project partners include Yosemite National Park, Stanislaus National Forest, and the U.S. Fish and Wildlife Service. The study area includes reaches of the Upper Tuolumne River mainstem and major tributaries regulated by the Hetch Hetchy Project, from O’Shaughnessy Dam to Don Pedro Reservoir, Cherry Creek downstream of Cherry Dam, and Eleanor Creek downstream of Eleanor Dam.
Background and approach for the Upper Tuolumne River Ecosystem Project
Recent work
- Amphibian surveys
- Fisheries surveys
- May 2008 experimental flood
- Sediment transport
- Temperature data assessment
