Instream Flows Policy


Policy for Maintaining Instream Flows in Northern California Coastal Streams (effective February 4, 2014)

The Policy for Maintaining Instream Flows in Northern California Coastal Streams (Policy) establishes principles and guidelines for maintaining instream flows for the protection of fishery resources, while minimizing water supply impacts on other beneficial uses of water, such as irrigation, municipal use, and domestic use. The Policy implements Water Code section 1259.4, which was added by Assembly Bill 2121 (Stats. 2004, ch. 943, § 3). The geographic scope of the Policy encompasses coastal streams from the Mattole River to San Francisco and coastal streams entering northern San Pablo Bay, and extends to five counties: Marin, Sonoma, and portions of Napa, Mendocino, and Humboldt Counties. The Policy applies to applications to appropriate water, small domestic use, small irrigation use, and livestock stockpond registrations, and water right petitions.

The Policy does not establish specific instream flow requirements for particular rivers or streams. Nor does the Policy approve any particular water diversion projects, or specify the terms and conditions that will be incorporated into water right permits, licenses, or registrations. Instead, the Policy establishes guidelines for evaluating the potential impacts of water diversion projects on stream hydrology and biological resources. The Policy includes principles to ensure that new water appropriations and changes to existing water right permits and licenses will not affect the instream flows needed for fish spawning, migration and rearing, or the flows needed to maintain natural flow variability, which protects the various biological functions that are dependent on that variability. The Policy also contains principles to ensure that migration paths to spawning and rearing habitats are not blocked.

Policy Implementation

The State Water Board has established a web page to provide information regarding the implementation of the Policy . The purpose of the web page is to keep interested persons informed of the State Water Board’s actions and to provide examples of activities that may be useful for prospective applicants, petitioners, or other parties. Additional information will be added as the State Water Board implements the provisions of the Policy.

Policy Timeline

  • On May 4, 2010, the State Water Resources Control Board adopted Resolution No. 2010-0021, adopting the Water Quality Control Policy for Maintaining Instream Flows in Northern California Coastal Streams (Policy) in accordance with California Water Code section 1259.4 (Cal. Code Regs., tit. 23, § 2921). The Policy became effective on September 28, 2010.
  • On October 16, 2012, the State Water Resources Control Board adopted Resolution No. 2012-0058, setting aside Resolution No. 2010-0021, thereby vacating the Board’s adoption of the Policy, as required by the Alameda County Superior Court in Living Rivers Council v. State Water Resources Control Board (Sup. Ct. Alameda County, 2012, No. RG10-543923).
  • On October 22, 2013, the State Water Resources Control Board adopted Resolution No. 2013-0035, re-adopting the Policy without any significant changes. The re-adopted Policy includes clarifications and clerical corrections to the language contained in the previous version of the Policy, adopted in 2010 and vacated in 2012. The re-adopted Policy became effective on February 4, 2014. The Division filed a Notice of Decision with the Secretary for Natural Resources on February 18, 2014.

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