San Francisco Bay Nutrients Project
San Francisco Bay Water Board staff has embarked on an effort working with the Southern California Coastal Water Research Program (SCCWRP) and the San Francisco Estuary Institute (SFEI) to develop nutrient numeric endpoints (NNE) for the San Francisco Bay Estuary. This effort is part of a statewide initiative, supported by the U.S. EPA Region IX and the State Water Board, to address nutrient over-enrichment (eutrophication) in State waters, specifically to develop the NNE framework for streams and lakes and for California’s coastal estuaries. The process for developing nitrogen and phosphorus nutrient criteria for California started in 1998 with the publication of the U.S. Environmental Protection Agency’s National Strategy for the Development of Regional Nutrient Criteria (USEPA, 1998). A key goal of this project is to develop a set of NNEs that can be used by the Water Board in our water quality programs.
Nationally, nutrient pollution, caused by excess nitrogen and phosphorus in the air and water, is one of America's most widespread, costly, and challenging environmental problems. Too much nitrogen and phosphorus in the environment can impact surface waters. Nutrients can cause algae to grow faster than ecosystems can handle, leading to adverse impacts to water quality, food resources, and habitats and to decreases in oxygen that fish and aquatic life need to survive.
The San Francisco Bay has not experienced nutrient related environmental problems, despite being recognized as nutrient-enriched, as it has long been considered resilient to the effects of nutrients. This is because in the estuary, the abundance of phytoplankton, microalgae that form an essential component of the aquatic food chain, has historically been lower than would be expected in a nutrient-enriched system due to a number of factors, including strong tidal mixing in the Bay; high Bay turbidity, which limits light penetration; and high filtration by clams. Changes recently observed in the Bay indicate that the Bay’s resilience to the effects of nutrients may be declining.
One outcome of the work done in support of NNE development was the development of a regional Nutrient Management Strategy. The overarching objective of the strategy is to avoid nutrient-caused impairments. The strategy calls for a collaborative effort to develop the science to support regulatory management decisions. Key goals of this effort include synthesis of the available scientific information and development of a science plan, continued development of nutrient objectives, development of a monitoring program to gather the observations necessary to support modeling of the Bay ecosystem’s response to nutrients, and development of implementation strategies
In 2014, a new NPDES watershed permit for nutrients from all municipal wastewater treatment facilities that discharge to San Francisco Bay. This permit is an important step in implementing the Nutrient Management Strategy. This permit covers more than 30 permittees that represent about two-thirds of the nutrient load to the Bay. The permit also contains requirements for technical studies to be conducted that will inform future Board consideration of the level of nutrient reduction that may be necessary to avoid Bay impairment and to increase the certainty that those reductions, if required at wastewater treatment plants, will produce the desired outcome.
To date, there has been an ongoing stakeholder advisory group (SAG) which has helped guide the development of the San Francisco Bay Estuary NNE and the strategy. Now the Water Board is working with stakeholders to develop a governance structure to guide implementation of the strategy and development of a regional science program. Moreover, a charter has been prepared describing the guiding principles of the Nutrient Management Strategy (NMS), its organizational structrure (see figure below), roles and responsibilities of participants as well as decision-making and communication protocols of various groups within the strategy.
For Stakeholder Advisory Group (SAG) Meeting Information: Please visit the SF Bay SAG Web Page for meeting agendas, presentations, and reports.
A Nutrient Technical Workgroup (NTW) has been formed to provide technical input on the work elements identified in the Nutrient Management Strategy. These workgroup meetings are anticipated to bring together stakeholders and experts on a variety of topics, including the assessment framework, monitoring plan development, modeling, science plan development and special studies design.
For Nutrient Technical Workgroup (NTW) Meeting Information: Please visit the SF Bay NTW Web Page for meeting agendas, presentations, and reports.
For information on science to support the Regional Nutrient Management Strategy: Please visit the San Francisco Estuary Institute's (SFEI) nutrient web page for details.
Science Plan Documents
- San Francisco Bay Nutrient Management Strategy - Science Strategy Annual Report FY 2016
- San Francisco Bay Nutrient Management Strategy - Science Plan (March 2016)
- San Francisco Bay Nutrient Management Strategy - Science Plan Peer Review Report (March 2016)
- The Zone of Impact of San Francisco Bay Outflow - Plume Patterns and Nearshore Distribution of Pollutants in the Gulf of Farallones (March 2016)
Nutrient Assessment Framework Documents
- See updated Assessment Framework documents on SAG web page
- White Paper - Approaches to a Nutrient Assessment Framework - Draft May 2013
Nutrient Related Background Documents
- U.S. EPA National Strategy for the Development of Regional Nutrient Criteria (1998)
- Technical Approach for Developing Nutrient Numeric Endpoints in California ( July 2006)
- Technical Approach for Developing Nutrient Numeric Endpoints California Estuaries (March 2007)
- U.S. EPA Nutrient Control Design Manual (January 2009)
- New and Improved U.S. EPA Website on Nitrogen and Phosphorus Pollution (July 2011)
Project Technical Reports
- Numeric Nutrient Endpoint Development for SF Estuary: Literature Review and Data Gaps Analysis - June 2011 Final Report
- San Francisco Bay Nutrient Management Strategy - November 2012 Final Report
- Suisun Bay Ammonium Synthesis Report - March 2014 Final Report
Data Collection/Loading Studies
- External Nutrient Loads to San Francisco Bay (draft, April 9, 2013)
- BACWA Nutrients Study Group Sampling Plan for Municipal Discharges
- Nutrients Study Sampling and Analysis Plan for Bay Area Refineries
- Water Board Order requiring submittal of information on nutrients in municipal wastewater discharges
- Water Board Order requiring submittal of information on nutrients in petroleum refinery wastewater discharges
- Archive file containing data for all facilities for period July 2012 through June 2014 (first seven quarters)
We have established a San Francisco Bay Stakeholder Advisory Group (SF Bay SAG) to guide the development of the NNE for the Estuary. The purpose of the SF Bay SAG is to advise the Water Board on the science and policy supporting NNE development and specifically to review background policy and technical information, provide stakeholder perspective and input on the NNE process and technical documents.The SAG also advises the Water Board on the selection of experts to be part of the Technical Team and the Scientific Advisory Panel.
- SF Bay SAG Web Page (contains meeting agendas, presentations, reports)
- Online poll concerning SAG facilitation and governance (poll completed)
- Draft Nutrient Strategy for SF Bay
- Bay Area Clean Water Agencies (BACWA) comments on Draft Nutrient Strategy
- Central Costa Costa Sanitary District comments on Draft Nutrient Strategy
- Sacramento Regional County Sanitation District comments on Draft Nutrient Strategy
- State and Federal Contractors Water Agency comments on Draft Nutrient Strategy
To receive email updates about this project, visit our email subscription page and sign up for the "Nutrients in San Francisco Bay" email list.
San Francisco Estuary Technical Team Committee
Technical Team members:
- James Cloern, United States Geological Service – Menlo Park
- Richard Dugdale, Romberg Tiburon Center – San Francisco State University
- Raphael Kudela, University of California at Santa Cruz
- Katharyn Bowyer, Romberg Tiburon Center – San Francisco State University
Initial Meeting December 2, 2010
Meeting #2 February 11, 2011
Aquatic Science Center website on Nutrients in San Francisco Bay
USGS San Francisco Bay Water Quality Monitoring
SCCWRP Web Site
Nutrients in Estuaries, A Summary Report of the National Estuarine Experts Workgroup 2005–2007 (November 2010)
For more information contact:
San Francisco Bay Regional Water Quality Control Board
1515 Clay Street, Suite 1400
Oakland, CA 94612