California approves Reclamation petition to capture flood flows

March 15, 2023
The U.S. Bureau of Reclamation will be able to divert flood water flows from March 15 through July 30 to recharge groundwater.

The California Water Resources Control Board announced that it has approved a petition by the U.S. Bureau of Reclamation to divert over 600,000 acre-feet of San Joaquin River flood waters for underground storage/recharge and wildlife refuges.

“Coming off the heels of the three driest years in state history, California is taking decisive action to capture and store water for when dry conditions return,” said Governor Gavin Newsom.

Reclamation’s petition requested a change to its San Joaquin River water rights at Friant Dam to manage flood flows. The board’s approval allows for diversions from March 15 through July 30.

“Important opportunities remain for potential water capture during the remainder of the wet season,” said Joaquin Esquivel, chair of the Water Resources Control Board. “We are grateful for Reclamation’s coordination with us to take advantage of this moment brought on by extreme weather to replenish California’s depleted aquifers. The board is working closely with partners like Reclamation, Department of Water Resources and other groundwater agencies to enable the capture and recharge of high flows, while also ensuring that projects happen in a way that protects communities, their access to drinking water, fish and wildlife, and water rights holders."

By submitting its petition, Reclamation helped the board make the scale of this potential recharge possible by avoiding the need for numerous individual approvals.

“We appreciate this decision by the State Water Board, which will allow us to take advantage of these expected flood flows for beneficial use,” said Ernest Conant, regional director of Reclamation's California-Great Basin Region. “With this year's record-breaking snowpack in the San Joaquin River Basin, Reclamation is diligently working to execute temporary water service contracts to ensure the best management of the projected large, unstorable flood flows.”

Most groundwater recharge occurs naturally during rain and flood events, when stormwater percolates through deeper layers of soil and into basins. Recent winter storms have helped snowpack and reservoirs, but basins recover more slowly. With groundwater accounting for up to 60% of California’s water supply in dry years, the state’s Water Supply Strategy seeks to expand replenishment of these basins — which have the ability to store eight to 12 times more water than the state’s surface water reservoirs — by 500,000 acre-feet annually.

Reclamation’s water rights allow it to store and divert water at Friant Dam primarily for municipal, domestic, irrigation and stock watering uses. That water is sent to Central Valley Project water contractors either south through the Friant-Kern Canal or north through the Madera Canal. Reclamation also releases water into the San Joaquin River for flood control, for riparian water right holders downstream of the dam, and for fish and wildlife enhancement purposes.

The approved order helps maintain restoration flows for fish while the groundwater recharge foreseen in the petition occurs, requiring that at least 300 cubic feet per second are bypassed to the San Joaquin River before additional diversions are permitted.

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