Unimpaired Flows

State and federal water quality laws—the federal Clean Water Act and California’s Porter-Cologne Act—require the State Water Resources Control Board to conduct period updates of the Sacramento-San Joaquin River Bay-Delta Water Quality Control Plan (Bay-Delta Plan).  Plan updates currently in progress seek to review and potentially amend Bay-Delta standards last updated in 2006.  The purpose is to review and update existing water quality standards in the Bay Delta and its extended watershed to afford reasonable protection for designated beneficial uses, including both municipal and industrial, agricultural, domestic, and environmental water quality standards.  Delta salt intrusion control updates and instream flows for salmon are notable features of the current update.  Additional information can be found on the Board’s website here.

• • Phase I – The Board adopted updated Southern Delta salinity standards and instream flow standards for fish in 2018.  The Board’s 2018 amendments relaxed the Bay-Delta Plan’s prior Southern Delta salinity standards.  On the Lower San Joaquin, the Stanislaus, the Tuolumne, and the Merced, the Board’s amendments set instream fish flow standards equivalent to 30 and 50 percent of runoff in each watershed, from February through June, with proposed year-round flow shifting of this total volume of water and on-going ‘adaptive management,’ starting at 40 percent.  This represents a large increase over historic flows and would have dramatic economic and water supply consequences for the affected region, especially in drier years.  The actual implementation of these new standards is a separate step and must take account of the impact on affected water rights priorities.  Pending litigation by several parties, including the California Farm Bureau, challenges the substitute environmental document underlying the Board’s Phase 1 update.  Addition information on Phase 1 can be found here.
  • Phase II – The second phase of the Board’s current Bay-Delta update applies to the Sacramento River and its tributaries and the remainder of the Delta.  The Board’s current proposal for this phase would seek between 45 and 65 percent of all spring runoff in the Sacramento River watershed, starting at 55 percent.  As with the Board’s Phase 1 standards, this amounts to an enormous volume of water above existing flows and would have devastating consequences for the Sacramento River region and, indeed, for the rest of the state.  The Board has yet to prepare any environmental document for this phase and has not yet proposed any actual, corresponding amendments to the Plan itself.  As with Phase I, the actual implementation of updated standards would require assignment of responsibility, including consideration of existing water rights.  Additional information on Phase II can be found here.
  • Voluntary Agreements – Proposed Bay-Delta voluntary agreements would substitute voluntary contributions of land, water, and funding over scientific research and other activities for water users in various parts of the extended Bay-Delta watershed in lieu of formal, regulatory implementation of the Board’s Phase 1 and Phase 2 standards.  Negotiations to define the details of these voluntary agreements have been underway for several years.  Information regarding the voluntary agreements can be found here.