West Coast Federal Energy Regulatory Commission (FERC) Licensed Hydroelectric Projects: Tuolumne River
Don Pedro (P-2299) and La Grange (P-14581) Hydroelectric Projects: Tuolumne River, CA
Project Profiles and Applicants
FERC Project No. P-2299: The Don Pedro Project is jointly owned by Turlock Irrigation District and Modesto Irrigation District (collectively, the Districts). The Project, situated at river mile 54.8 on the Tuolumne River, was completed in 1971. It consists of a 580 ft. high dam which creates a 2,030,000 acre-foot (ac-ft) reservoir covering approximately 13,000 acres in southwest Tuolumne County. A powerhouse with a generating capacity of 168 megawatts sits at the base of the dam.
The dam and reservoir replaced the former, and much smaller, Don Pedro Dam located about 1.5 miles upstream. The City and County of San Francisco (CCSF), which operates hydro and water supply projects further upstream in the Tuolumne River watershed, contributed financially to the construction of the Project in order to be relieved of its flood control obligations and obtain a water banking privilege in the new reservoir. The banking arrangement allows CCSF to pre-release flows from its upstream facilities into the Don Pedro Reservoir so that at other times it can hold back an equivalent amount of water that otherwise would have had to be released to satisfy the Districts’ senior water rights.
Both the elimination of the flood control responsibility and the creation of the water bank provide CCSF with greater flexibility in its upstream water and power operations. The U.S. Army Corps of Engineers also contributed to the construction of the Project in order to create 340,000 ac-ft of seasonal flood control space.
FERC Project No. 14581: The 4.75 megawatt La Grange Project is located at La Grange Dam on the Tuolumne River in Stanislaus and Tuolumne counties, California. The Project is jointly owned by the Turlock (TID) and Modesto irrigation districts (Districts), although only TID owns and operates the Project’s Powerhouse. La Grange Dam provides head for consumptive water diversions into the Districts’ canal systems, for non-consumptive power generation, and acts as an afterbay to the New Don Pedro/P-2299 FERC Project (also owned by the Districts). The two Projects are operated in coordination by the Districts and are on the same FERC licensing pathway.
Federally Threatened - Listed Species/Species of Concern
- The distinct population segment (DPS) of California Central Valley (CV) steelhead (Oncorhynchus mykiss) and its critical habitat;
- The evolutionarily significant unit (ESU) of spring-run Chinook salmon (O. tshawytscha) and its critical habitat;
- The DPS of North American green sturgeon (Acipenser medirostris) and its critical habitat;
- The ESU of CV fall-run Chinook salmon (O. tshawytscha) [Species of Concern]
FERC Relicensing Status
The Districts filed their Amended Final License Application for the Don Pedro Project and their Final License Application for the La Grange Project with FERC in October 2017. NOAA Fisheries filed preliminary protection, mitigation and enhancement measures and fishway prescriptions under the Federal Power Act in January 2018.
These measures included improvements to flow and physical habitat intended to mitigate the negative impacts of the Projects on NOAA Fisheries trust resources. FERC subsequently released a Draft Environmental Impact Statement for both Projects in February 2019. FERC will release a Final Environmental Impact Statement and then initiate a consultation with NOAA Fisheries under Section 7 of the Endangered Species Act.
- MID and TID Don Pedro Project Relicensing
- TID and MID La Grange Project Relicensing
- Federal Energy Regulatory Commission
- FERC eLibrary, Docket P-2299/P-14581