The water that is stored in Don Pedro Reservoir (the 5th largest reservoir in the state of California) is allocated to Turlock Irrigation District and Modesto Irrigation District, who have senior water rights dating back to the 1880’s. Additionally, the City and County of San Francisco utilizes the reservoir for backup storage for its Hetch Hetchy project, thus having junior water rights and an interest in its management. The land surrounding the reservoir is managed by the Bureau of Land Management (BLM). And finally, the Federal Energy Regulatory Commission (FERC) administers the license that controls the dam and water releases for municipal and agricultural users downstream, for fisheries in the lower Tuolumne River, and to generate hydro-electric power. In the next few years, the conservation community will be keeping close tabs on two major projects that will affect how Don Pedro is managed.

Red Mountain Bar Project      Turlock Irrigation District and Modesto Irrigation District are moving forward on plans to build a large pumped storage project above Don Pedro Reservoir. The project would involve constructing a dam 1,700 feet across and 465 feet high across a ravine above Don Pedro. The new reservoir would span an area of 244 acres with a capacity of 35,000 acre feet of water, and connect to powerhouse, intake structure, and a tunnel connecting it to Don Pedro, in addition to a 47-mile long transmission line to transmit the electricity to the Central Valley. The intent of the project is to create a backup power supply for the districts by pumping water uphill from Don Pedro at night to the new reservoir when energy is cheaper, then releasing it to generate electricity during peak hours when there is a greater demand. Artist rendering of the proposed Red Mountain Bar project      Building a new reservoir would undoubtedly result in negative impacts to the environment surrounding Don Pedro, to the reservoir itself, and to those who recreate there. A number of conservation groups have filed motions to intervene in the process, which gives the groups legal standing during formal proceedings for the project. These groups include CSERC, the Tuolumne River Trust, Friends of the River and various fly fishing organizations who are concerned with downstream impacts. In addition to conservation groups, the Department of Interior (BLM), San Francisco Public Utility Commission (SFPUC) and the County of Tuolumne have filed motions to intervene. At this time, because the project is only in the feasibility analysis phase, there has been no formal application yet filed for development of the project. However, the Districts have already spent millions of dollars on preliminary studies, which underscores the fact that they are seriously moving forward with this massive project.        The reservoir would be located immediately adjacent to the BLM Red Hills Area of Critical Concern, which contains special soils that support rare and endemic plant species such as the Chinese Camp Brodiaea, Red Hills Verbena and Butterweed (which has been found within the proposed project footprint). BLM has expressed concerns that the roads and infrastructure necessary for this project could have a significant negative impact on these rare species.

Don Pedro Relicensing

     Turlock and Modesto Irrigation Districts are gearing up to renew their Federal Energy Regulatory Commission License (FERC) to operate the dam at Don Pedro Reservoir. The existing 1966 license is set to expire in 2016, and the complex process has already begun. The FERC license is an agreement between the districts and the federal government that dictates how the dam and reservoir is managed, including reservoir levels and releases for downstream users. In the last 50 years we have gained a better understanding of how reservoirs and dam facilities can be operated in a manner that is beneficial to not only the utility districts that provide water and power, but also to fish and wildlife downstream. Conservation groups view the Don Pedro license renewal as an opportunity to secure better protections for the natural resources on the lower Tuolumne River.

     The lower Tuolumne River is not in good shape - water quality does not meet Clean Water Act standards and the native fall run Chinook Salmon population has experienced a devastating decline over the last 20 years from tens of thousands to just a few hundred each year. It’s critical that flows and temperatures in the river are managed so that salmon reach the upper reaches to spawn and that the cycle continues with their journey back to the ocean. Salmon and other native fish are an indicator of overall ecosystem health in the river as they provide an important food source for a number of animal species such as river otters and birds and contribute to the overall nutrient cycle.

     Conservation groups see the Don Pedro relicensing as a “once in 50 years” opportunity to shape the process for managing the lower Tuolumne River to ensure for a sustainable future for fish and wildlife and their habitat. How the river is managed is also important for the thousands of people who fish, boat and sightsee on the river. These groups will play an important role as not only “watchdogs” during the process, but also in providing important local information that will be valuable to FERC and the other agencies that will be closely involved in the process, such as the Fish and Wildlife Service, National Marine Fisheries Service, the State Water Board, and the Department of Fish and Game.

      Currently, FERC and the utility districts are in the pre-application phase of the process where all relevant information such as legal and scientific data is being compiled. CSERC, along with our conservation partners, will be following this process closely, to make sure that Don Pedro is managed to protect wildlife habitat and recreational values downstream.

RETURN TO CSERC HOMEPAGE