Salmon Survival Engineering Solutions

Under the National Marine Fisheries Service (NMFS) 2009 Biological Opinion and Conference Opinion on the Long-Term Operations Of The Central Valley Project and State Water Project (BiOp) Reasonable and Prudent Alternative (RPA) Action IV.1.3 (Action) the Department of Water Resources (DWR) and U.S. Bureau of Reclamation (USBR) are required to consider engineering solutions to further reduce the diversion of emigrating juvenile salmonids to the interior and southern Delta and reduce exposure to Central Valley Project (CVP) and State Water Project (SWP) export facilities.  DWR’s South Delta Branch has led the RPA compliance work and is working towards the implementation of engineering solutions intended to benefit salmon populations and maintain CVP and SWP water supply reliability. 

The Action has been organized into a multi-year study consisting of three phases:

Phase I – Initial Findings (2011-2013)

During Phase I, a Technical Working Group (TWG) was established.  This TWG reviewed possible locations to reduce the diversion of salmonids and proposed possible engineering solutions for consideration.

Phase II – Recommended Solutions (2012-2015)

Phase II conducted detailed evaluations of options considered during Phase I, conducted field studies, prepared conceptual barrier design details, and based on existing information, developed recommended engineering solutions for each of the five study locations:

  1. Georgiana Slough (Sacramento River)
  2. Three-mile Slough (Sacramento River)
  3. Head of Old River (San Joaquin River)
  4. Turner Cut (San Joaquin River)
  5. Columbia Cut (San Joaquin River)

DWR performed field studies at Georgiana Slough (2011 and 2012) and at the Head of Old River (2009 and 2010) to assess the effectiveness of a non-physical barrier design (Bio-Acoustic Fish Fence, or BAFF).  In 2014, the effectiveness of a physical barrier design (Floating Fish Guidance Structure, or FFGS) was studied at Georgiana Slough.

Phase III – Implementation of Preferred Option 

Phase III consists of DWR and USBR working collaboratively with NMFS to consider implementing engineering solution approaches.

Currently, in an effort to boost salmonid populations, we have developed a project concept, the Salmon Protection Technology Study (SPTS), to construct and operate barriers at Delta junctions with known lower survival salmonid migratory pathways. We continue studying other emerging salmonid barrier technologies while collecting salmonid survival and behavioral data.

The SPTS project is based on the best available science. Its design includes planning and conducting a 5-year fish diversion and salmon protection technology implementation program and evaluation in the Sacramento River using a Bio-Acoustic Fish Fence (BAFF), Floating Fish Guidance Structure (FFGS), or Infrasound Fish Fence at locations that will provide the largest resource benefit. Locations under consideration include Georgiana Slough, Steamboat Slough, and Sutter Slough. The evaluation of the efficacy of these technologies will provide the basis for DWR to recommend to National Marine Fisheries Service (NMFS) future actions beyond SPTS that will continue to enhance the salmon populations and avoid adverse impacts to SWP and CVP operations.

As a result of the 2009 NMFS BiOp, the SWP and CVP operations must comply with Reasonable and Prudent Alternative Action IV.1.3 to reduce diversion of juvenile salmonids into the central and south Delta. Currently, the presence of endangered salmon species in the south Delta require significant SWP and CVP operations curtailments, even though the science that links SWP and CVP operations curtailments to improved salmon survival is not well developed and inconsistent.

The SPTS project will provide the best available science and engineering for the final implementation of Salmon Survival Engineering Solutions Phase III, and is informed by the NMFS BiOp Action IV.1.3 and Georgiana Slough Study Reports linked below.


  • August 2019 - Submit Project Permit Applications
  • July 2020 - Receive Project Permits/Begin Construction
  • January 2021 - Complete Construction/Initiate First Barrier Operations Season with Efficacy Testing
  • June 2025 - Last Barrier Operational Season with Efficacy Testing

Contact Information

Requests for information about this project may be directed to:

William McLaughlin
Senior Water Resources Engineer
Bay-Delta Office
California Department of Water Resources
1416 Ninth Street
Sacramento, CA 95814


Telephone: (916) 653-0628  Fax: (916) 653-6077


Salmon Survival Engineering Solutions  Bio-Acoustic Fish Fence in operation

2011-2012 Bio-Acoustic Fish Fence in operation