Last week, the State Water Resources Control Board (State Water Board) released their third, and final, draft for the proposed Bay-Delta Plan. This proposed draft, considered a Substitute Environmental Document (SED), establishes new flow water quality objectives on top of pre-existing drinking water quality standards, irrigation supply, as well as fish and wildlife habitat supply requirements for the Bay-Delta Region. The SED sets flow requirements for the Lower San Joaquin River and the three salmon-bearing tributaries connected the Stanislaus, Tuolumne and the Merced Rivers. The plan also revises the salinity water quality objectives in the southern Delta. This action comes in response to several studies showing decline in native species in the Delta, specifically the reduction in Chinook Salmon, as well as the degradation of habitat for the various other species within the aquatic regions.
The revised plan sets flow requirements for certain times of the year to be maintained by all Lower San Joaquin River tributaries, which in turn will reduce the amount of water made available to agricultural and urban water users. The proposed plan sets the unimpaired flow releases to be set at 40% to provide adequate habitat and wildlife support from February to June. The State Water Board evaluated the potential impact to other water users along these tributaries and acknowledged the impact to agricultural operations, as well as the future reliance on groundwater with the reduction in surface water availability. The Sustainable Groundwater Management Act (SGMA) will also lessen the amount of available water in the upcoming years, and so the State Water Board is encouraging these affected regions to look for other ways to make the water available last longer through enhanced groundwater recharge projects as well as encouraging irrigation efficiency upgrades. In the end, these upgrades will only do so much, and the implementation of SGMA as well as these unimpaired flow requirements only puts agriculture in a more difficult position.