Science Synthesis

Synthesis involves integrating existing data and information in new analyses to address new scientific questions. The Delta Science Program leads and coordinates syntheses on key scientific issues important to management of the Sacramento-San Joaquin Delta. These collaborative efforts aim to update the state of scientific knowledge, guide adaptive management, and identify science needs and data gaps.

To promote open access to synthesis data among scientists, managers, and the public, the Delta Science Program uses Shiny – a digital interface for creating interactive point-and-click applications with the statistical programming language R. Those developing Shiny applications, with a connection to the Sacramento-San Joaquin Delta, are encouraged to submit an application to be featured on the Delta Science Program’s Shiny account. For more information, please contact

Active Synthesis Efforts

Periodically released collections of peer-reviewed articles for scientists and policy makers that synthesize the “state of the science” of topics relevant to management of the Bay-Delta system. The 2008 edition of SBDS is available upon request via, while the 2016 edition can be accessed via the SBDS web page. The next edition is anticipated to be released in 2022 and will feature a suite of articles describing ecosystem services and disservices of primary producers.

This effort, led by the Delta Science Program in partnership with the National Center for Ecological Analysis and Synthesis (NCEAS), provides high-quality training in synthetic data science and statistical techniques and offers an opportunity for enhanced collaboration between agency and academic scientists in a focused working group. The group leverages training and a collaborative setting to analyze drivers of the Delta’s estuarine food supply. Products from this working group will offer strong scientific support to inform decision-making for restoration, the protection of endangered species, and the management of flow actions. More information about the effort, including resources developed for the working group events, are available on the DSP-NCEAS web page.

The Delta Smelt is an endangered fish species native to the Sacramento-San Joaquin Delta. The Delta Smelt Conditions Report was produced for the Collaborative Adaptive Management Team (CAMT) to provide an overview of the environmental conditions that are considered important for the species. The report provides graphical depictions of conditions as they change through time from 2002 – present, across 7 geographic regions. Metrics include abiotic (non-biological) indicators such as flow and salinity, as well as biotic (biological) indicators such as phytoplankton (microscopic algae) and invasive clams. “Indices” or metrics gaging the population status of Delta Smelt are also provided from the major Interagency Ecological Program (IEP) surveys.

The Delta Smelt Conditions Report is updated on an annual basis once all data from the prior year are available. The report is produced by the Delta Science Program and reviewed by CAMT before publication. Contact with questions.

Life history diversity has emerged as an important metric for fish population resilience and conservation. However, for juvenile salmon, life-history is difficult to quantify, and resource managers have traditionally relied upon an oversimplified approach. To address this issue, this study uses acoustic telemetry data collected previously for survival studies to better assess diversity in migration timing. This is a logical next step for acoustic data; towards understanding how juvenile salmon use these river reaches of interest to navigate the risks and rewards of freshwater residency. Visit the Delta Science Program’s Shiny account to view data from this study in an interactive map app.

Zooplankton are small floating animals too small and weak to swim against currents, and are important food sources for many fishes in the Delta, such as salmon, sturgeon, and Delta Smelt. Since 1972, zooplankton have been continuously monitored in the region by the IEP. The Delta Science Program’s zooplankton synthesis efforts are part of a collaborative, multi-faceted and ongoing effort.

  • Data Integration and open data access: A collaborative effort between the Delta Science Program, the California Department of Water Resources (DWR), and the California Department of Fish and Wildlife (CDFW) which integrated zooplankton data from five major surveys into a comprehensive dataset comprised of over two million data points from over eighty thousand zooplankton samples. The integrated dataset can be accessed via the Delta Science Program’s Shiny account, R package, or data publication.
  • Report on Zooplankton Monitoring in the Delta: A detailed report on zooplankton monitoring in the Delta with recommendations for improvement has been published as an IEP technical report.
  • A symposium on zooplankton ecology and monitoring was hosted in October 2020.
  • Current efforts are focused on hosting workshops on zooplankton taxonomy and analyzing the integrated dataset for relationships among habitat characteristics and zooplankton abundance, at both the species and community levels.

Mercury is a legacy contaminant that has haunted natural resource managers in the Bay-Delta region for decades. Methylmercury, the most toxic form of mercury, is associated with adverse effects to fish, wildlife, and humans. The Delta Science Program, in collaboration with the U.S. Geological Survey (USGS), Delta Conservancy, and CDFW, coordinated a series of workshops in January and June 2016. This mercury synthesis effort is the first in over a decade and will present the most up-to-date scientific information while also identifying crucial gaps in knowledge.

Past Synthesis

Please contact with questions about access to or the status of a particular synthesis.

Title Description Date(s) of effort Product(s)
2012-2016 Drought Management and Science Synthesis A concise synthesis on the management decisions made during the 2012-2016 drought, and the scientific information utilized to inform those decisions. Lessons learned from these actions are discussed to inform future drought-related management decisions. 2015-2020 Synthesis report: Drought and the Sacramento-San Joaquin Delta, 2012–2016: Environmental Review and Lessons (Durand et al. 2020)
False River (Emergency Drought) Barrier This synthesis summarizes the various studies examining the ecological responses to a rock barrier constructed in False River during the spring of 2015 to limit salinity penetration into the central Delta and to the water intakes in the south Delta. 2015-2019 Synthesis report: Effects of Drought and the Emergency Drought Barrier on the Ecosystem of the California Delta (Kimmerer et al. 2019)
Ecological and Physiological Impacts of Salinization of Aquatic Systems from Human Activities A symposium was held with the UC Davis Coastal and Marine Sciences Institute (UCD CMSI) to discuss how changing salinity regimes affect the Bay-Delta and other estuarine ecosystems. September 26, 2018 Synthesis report: Ecological Effects of Climate-Driven Salinity Variation in the San Francisco Estuary: Can We Anticipate and Manage the Coming Changes? (Ghalambor et al. 2021)
Symposium video recording:
Salmon Disease Ecology Symposium A symposium and workshop were held with the UCD CMSI to discuss what is known about pathogens and diseases in wild salmon populations in the Central Valley, what monitoring and research gaps exist, and how other systems manage to control or reduce impacts of pathogens/disease. March 18, 2018 Synthesis report: Disease in Central Valley Salmon: Status and Lessons from Other Systems (Lehman et al. 2020)
Symposium video recording:
Managed Relocation Under a Changing Climate A symposium was held with the UCD CMSI with the goal of informing scientists and managers on decision-making processes for translocations. December 4, 2017 A synthesis report is in progress.
Symposium video recording:
Informing Delta Management Using Biotelemetry A symposium was held with Cramer Fish Sciences and the Biotelemetry Laboratory at UC Davis to discuss challenges and management insights related to telemetric technology. November 9, 2017 A synthesis report is in progress.
Symposium video recording:
Delta Invasive Species A symposium held with the Delta Interagency Invasive Species Coordination Team (DIISC Team) and UC Davis to explore tools and actions being developed to meet today’s invasive species management needs. August 29, 2017 A synthesis report was not produced.
Symposium video recording:
Contaminants in the San Francisco Bay-Delta: Novel Tools and Approaches to Evaluate Effects of Multiple Stressors A symposium was held with the UCD CMSI and the State Water Resources Control Board discussing the impacts of multiple stressors on aquatic ecosystems. January 31, 2017 Synthesis report: Review of and Recommendations for Monitoring Contaminants and their Effects in the San Francisco Bay−Delta (Connon et al. 2019)
Science Enterprise Workshop In partnership with the USGS, a workshop brought scientists, science-policy experts, and stakeholders together to discuss how collaborative science is being managed, funded, and communicated in several high-profile ecosystems around the country. November 1-2, 2016 Proceedings report:
Executive summary:
Workshop video recording:
Delta and Longfin Smelt: Is Extinction Inevitable? A symposium held with the UCD CMSI discussing the status and decision-making efforts related to Delta and longfin Smelt. March 29, 2016 Synthesis report: Is Extinction Inevitable for Delta Smelt and Longfin Smelt? An Opinion and Recommendations for Recovery (Hobbs et al. 2017)
Symposium video recording:
Primary Production A workshop held by the Delta Science Program and San Francisco Estuary Institute. October 2015 Synthesis reports:
Primary Production in the Delta: Then and Now (Cloern et al. 2016)
Primary Production in the Sacramento-San Joaquin Delta: A Science Strategy to Quantify Change and Identify Future Potential (Robinson et al. 2017)
Invasive Aquatic Vegetation A symposium held with DIISC Team and UC Davis to explore new developments in surveillance and monitoring of aquatic vegetation. September 15, 2015 Synthesis report: Invasive Aquatic Vegetation Management in the Sacramento–San Joaquin River Delta: Status and Recommendations (Ta et al. 2017)
California Salmon and Climate Variability A symposium held with the UCD CMSI on how changing ocean and hydrologic conditions affect Central Valley salmon and their management. September 10, 2015 Symposium video recording:
Sturgeon in the Sacramento-San Joaquin Watershed - New Insights to Support Conservation and Management A symposium held with the Center for Aquatic Biology and Aquaculture about the physiology, behavior, and ecology of sturgeon to help guide management and conservation efforts. March 3, 2015 Synthesis report: Sturgeon in the Sacramento–San Joaquin Watershed: New Insights to Support Conservation and Management (Klimley 2015)
Enhancing the Vision for Managing California’s Environmental Information The Environmental Data Summit brought together scientists, resource managers, decision-makers, academia, stakeholders, and others to discuss a new era in information management and discovery. The resulting white paper “Enhancing the Vision for Managing California’s Environmental Information” was used in the development of Assembly Bill AB1755, signed by the Governor in November 2016. June 5-6, 2014 A white paper entitled “Enhancing the Vision for Managing California’s Environmental Information” was produced. To request a copy of this report, please contact
Interior Delta Flows and Related Stressors A workshop identifying the best available science to inform the State Water Resources Control Board’s decisions pertaining to interior Delta flows April 16-17, 2014 To request a copy of the final panel report, please contact
Delta Outflows and Related Stressors A workshop held to inform the State Water Resources Control Board’s decisions regarding Delta outflow objectives. February 10, 2014 To request a copy of the final panel report, please contact
Fish Predation on Central Valley Salmonids in the Bay-Delta Watershed A workshop held by the Delta Stewardship Council, CDFW, and National Marine Fisheries Service. July 22-23, 2013 To request a copy of the final panel report, please contact
Tidal Marshes and Native Fishes in the Delta: Will Restoration Make a Difference? A symposium and workshop held with the Center for Aquatic Biology and Aquaculture and American Fisheries Society on the science of ecological linkages between tidal marshes and fish in the Delta. June 10, 2013 Synthesis report: The Role of Tidal Marsh Restoration in Fish Management in the San Francisco Estuary (Herbold et al. 2014)
The Science of Natural Functional Flows to the Delta A symposium and workshop held with the Center for Aquatic Biology and Aquaculture discussing aspects of functional flow regimes in the Delta. January 18, 2013 Synthesis report: Functional Flows in Modified Riverscapes: Hydrographs, Habitats and Opportunities (Yarnell et al. 2015)
Salmonid Lifecycle Models A workshop to inform agencies implementing the 2009 Biological Opinions on how salmonid life cycle models could be used in a decision-making framework. April 13, 2011 A panel report was produced. To request a copy of this report, please contact