Three dam expansion projects could increase water storage for use in the Central Valley by a whopping 304,000 acre feet.
Each of the projects would raise existing dams, not build new ones.
The project that is furthest along would raise the B.F. Sisk Dam in Merced County to expand San Luis Reservoir storage by 130,000 acre feet.
Two other projects are just at the proposal stages. One would raise the Buchanan Dam in Madera County to boost storage in H. V. Eastman Lake by 50,000 acre feet. And another would increase Pine Flat Dam in Fresno County to increase that lake’s capacity by 124,000 acre feet.
The Bureau of Reclamation and San Luis & Delta-Mendota Water Authority celebrated the approval of the Sisk Dam project at an event Oct. 20 at San Luis Reservoir.
The expansion and dam raise is a joint project between the two agencies and has received a stream of federal funding.
In 2022, $25 million was invested in the project under President Biden’s Bipartisan Infrastructure Law with another $10 million added this year. The project is also approved for $60 million from the federal Water Infrastructure Improvements for the Nation (WIIN) Act.
The project’s construction timeline is still under development according to a spokesperson for the Bureau of Reclamation.
That comes alongside another 10-foot raise of the dam for seismic safety improvements. The seismic raise is a separate $1 billion-dollar endeavor.
The additional space in the reservoir will allow for more water to be delivered to contractors south of the Sacramento-San Joaquin Delta, including the giant Westlands Water District, other ag districts and wildlife refuges.
“The ability to capture more water in the years it is available, particularly given California’s changing climate, is a critical component of a more secure future for the communities, farms and wildlife dependent on the Central Valley Project for their water supply,” said Cannon Michael, board chair of the San Luis & Delta-Mendota Water Authority, in a press release. “We value our partnership with the Bureau of Reclamation and look forward to completion of this vital water storage project.”
The last few years were a stark demonstration of that climate variation with extreme drought gripping the state from 2020-2022 followed by an epic wet winter in 2023.
In Madera County, the Chowchilla Water District is spearheading an effort to raise the Buchanan Dam on Eastman Lake.
“We know it’s gonna be a hell of a lift,” said Brandon Tomlinson, general manager of the Chowchilla Water District. “But we decided to go after it.”
The dam would be raised by 24 feet and a 700-foot saddle dam would be built to help accommodate water storage. That would increase capacity from 150,000 acre feet to 200,000 acre feet, said Tomlinson.
The idea for the project started back in 2014 in response to the state’s Sustainable Groundwater Management Act which requires agencies in overpumped areas to bring aquifers back into balance by 2040.
The dam is operated by the Army Corps of Engineers, which must give the project a green light. The project still needs a feasibility study approved which could potentially come in 2024.
In Fresno County, the Kings River Conservation District is also working toward a feasibility study to raise Pine Flat Dam. The dam would be raised by 12 feet to increase the lake’s existing 1 million acre feet of storage by 124,000 acre feet.
The project would cost somewhere between $800 million and $1 billion, said David Merritt, general manager of Kings River Conservation District.
The project needs further study with the Army Corps, said Merritt. And staff are trying to lock down funding for a feasibility study which could cost around $500,000, he added.
The project would help minimize downstream impacts during floods, said Merritt.
This year, severe floods overwhelmed valley infrastructure, swamping valley communities and reforming the Tulare Lake in Kings County. Projects such as the dam raise could help to minimize those impacts, said Merritt.