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Ocean Standards -Desalination Facilities & Brine Disposal

Ocean Standards

desalination facilities and brine disposal

State Water Board staff is developing an amendment to the Ocean Plan that would address issues associated with desalination facilities (Desalination Amendment). Desalination facilities and brine disposal were identified as Issue Number 4 in the 2011-2013 Triennial Review Workplan because several new desalination facilities have been planned along the California coast to augment existing water supplies.

The operation and construction of desalination facilities can result in marine life mortality and harm to aquatic life beneficial uses. During the process of ocean desalination, organisms may be drawn in with the source water and enter the facility’s water processing system. Salt and minerals are removed from salt water to produce fresh water and organisms do not survive the desalination process. The salt, minerals, and other compounds produced as a by-product of desalination are discharged into the ocean as hyper-saline brine. Brine is denser than the receiving ocean water and, depending on discharge methods, may settle on the seafloor and have adverse effect on marine organisms.

Currently, the Water Boards regulate brine discharges from these types of facilities through the issuance of National Pollutant Discharge Elimination System (NPDES) permits that contain conditions protective of aquatic life. However, the Ocean Plan does not yet have an objective for elevated salinity levels in the ocean, nor does it describe how brine discharges are to be regulated and controlled, leading to permitting uncertainty. The Ocean Plan also does not address possible impacts to marine life from new intakes for desalination facilities.

The State Water Board is considering amendments to the Ocean Plan that would address desalination facilities. The proposed Desalination Amendment would include components that: 1) clarify the State Water Board’s authority over desalination facility intakes and discharges, 2) provide direction to the regional water boards regarding the determination required by California Water Code section 13142.5, subdivision (b) (hereafter 13142.5(b)), 3) include implementation provisions for a statewide narrative receiving water limitation for salinity, and an option for dischargers to apply for a facility-specific receiving water limitation, and 4) include monitoring and reporting requirements.


  • Draft Final Desalination Amendment with Draft Final Staff Report with Substitute Environmental Documentation was released April 24, 2015
  • Fact Sheet Updated April 24, 2015 available here: Fact Sheet

Public Meetings

Scientific Peer Review

Pursuant to Health and Safety Code section 57004, the proposed Desalination Amendment and draft Staff Report, including the draft Substitute Environmental Document, were subject to external scientific peer review through an interagency agreement with the University of California. Peer review was solicited on June 18, 2014 and was completed on September 17, 2014. Responses to External Scientific Peer Review comments can be found in Appendix I of the draft Final Staff Report with draft Final SED associated with the draft Final Desalination Amendment.

State Water Board Contracted Expert Panels and Studies

As part of the development of the amendment, staff has initiated four studies to gather scientific data and get technical input and scientific recommendations on key desalination issues. The three expert panels have finalized their findings and recommendations and an additional salinity toxicity study has also been completed.  

Expert Panel III on Intake Impacts and Mitigation

The Expert Review Panel on Intake Impacts and Mitigation was reconvened to address the questions raised at the January 30, 2013 Stakeholder Meeting at Moss Landing Marine Laboratory. The State Water Board contracted with the Moss Landing Marine Laboratory to establish an expert panel to address issues associated with potential effects of discharge diffusers on marine life and provide a further explanation of the mitigation ‘fee’ approach for the entrainment impacts caused by surface intakes at desalination facilities. The panel members are Dr. Michael Foster, Dr. Gregor Cailliet, Dr. John Callaway, Dr. Kristina Mead Vetter, Dr. Peter Raimondi, and Dr. Philip Roberts.

A Draft Report was submitted to the State Water Board staff September 15, 2013. A Final Report was submitted on October 9, 2013.

Salinity Toxicity Studies

Researchers at the Marine Pollution Studies Laboratory at Granite Canyon determined the tolerance of Ocean Plan test species to various concentrations of hyper-saline brine. Toxicity tests followed U.S. EPA methods. The results of the tests were used to calculate no observed effect concentrations (NOECs), lowest observed effect concentrations (LOECs), and median lethal or median effects concentrations (LC50 or EC50) for each test protocol and endpoint. Toxicity tests were also conducted using brine effluent samples from a desalination facility.

Expert Panel II on Intake Impacts and Mitigation

The State Water Board contracted with the Moss Landing Marine Laboratory to establish an expert panel to address issues associated with minimizing and mitigating intake impacts from power plants and desalination facilities. The panel members were Dr. Michael Foster, Dr. Greg Cailliet, Dr. Jim Callaway, Dr. Pete Raimondi, and Mr. John Steinbeck. The panel met on August 8, 2011 and on November 15, 2011.  A public meeting was held March 1, 2012 at the Moss Landing Marine where panel members presented  their recommendations and took  questions and comments from the public on the panel’s Draft Report.  Updates were given on the other two studies.  The panel  members deliberated and made changes to their report, which was finalized on March 14, 2012 Expert Review Panel on Intakes: Final Report.

Expert Panel I on Impacts and Effects of Brine Discharges

The State Water Board contracted with the Southern California Coastal Water Research Project (SCCWRP) to establish a panel of experts in the fields of oceanography, plume modeling, ecotoxicology, and marine ecology to answer the following questions related to brine discharge:

  1. What are the potential environmental impacts?
  2. What disposal strategies will minimize impacts from brine discharges?
  3. What models should be applied to predict how brine plumes will behave?
  4. Can cumulative water quality effects associated with multiple brine plumes be evaluated with models?
  5. What are appropriate monitoring strategies for brine discharges?

A public meeting was held July 5, 2011 in Sacramento to describe the project and solicit input regarding panel members and issues. The panel met several times to develop recommendations for the State Water Board. The panel released a draft report , solicited input from the public, and held a public meeting on December 8-9, 2011. The panel met again in February 2012 and a submitted a Final Report with their findings and recommendations to the State Water Board. The related materials can be found on the SCCWRP website.

Studies Submitted to the State Water Board

West Basin Municipal Water District (WBMWD) High-Salinity Sensitivity Study

The WBMWD High Salinity Sensitivity Study evaluated the potential short-term and long-term exposure effects of high salinity discharges from the WBMWD ocean water desalination demonstration facility (OWDDF) on aquatic organisms representative of communities indigenous to various near shore environments in Southern California. Short-term effects were evaluated using Whole Effluent Toxicity (WET) bioassays developed by the U.S. Environmental Protection Agency to quantify the magnitude and threshold of potential biological effects of discharges (e.g. treated wastewater). Both acute toxicity (mortality effects) and chronic toxicity (mortality + sub-lethal effects) bioassays were performed by a state accredited bioassay laboratory. Long-term effects were evaluated using mesocosm procedures performed at the OWDDF by exposing multiple organisms for eight weeks to ambient seawater and diluted brine flows from the OWDDF in large aquaria constructed to simulate the OWDDF discharge environment.

Questions or Comments?

Please Contact:  Claire Waggoner or phone (916) 341-5582