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
The San Francisco Public Utilities Commission (SFPUC) owns and operates the Hetch Hetchy Water and Power system. This system, located in the upper Tuolumne River watershed, includes dams and flow diversions on the Tuolumne River, Cherry Creek (a tributary to the Tuolumne River), and Eleanor Creek (a tributary to Cherry Creek). As part of establishing a common foundation of environmental information for the river and stream reaches affected by operation of the Hetch Hetchy system, the SFPUC Natural Resources and Hetch Hetchy Water and Power Divisions have embarked on an intensive one-year effort to describe current ecological and geomorphic conditions in the Tuolumne River from O’Shaughnessy Dam to New Don Pedro Reservoir, Cherry Creek downstream of Cherry Lake Dam, and Eleanor Creek downstream of Lake Eleanor Dam. Numerous agencies and other stakeholders are also contributing to this study, including the Yosemite National Park Service, U.S. Fish and Wildlife Service, and the U.S. Forest Service. Read more
The objectives of this report are to begin informing existing Hetch Hetchy Project operations to promote opportunities to protect ecologic and geomorphic values within the context of meeting current water supply, power generation, and water quality objectives, and minimum flow requirements; describe key flow-related river ecosystem processes and how these processes are affected by historical and current Hetch Hetchy Project operations; guide future work to better understand the relationship between the Tuolumne River ecosystem and Hetch Hetchy Project operations; and identify short- and long-term annual monitoring activities necessary to support this work. Read more
