discoveries from 4 decades of studies
by Jim Cloern, Senior Research Biologist
Water Quality of San Francisco Bay Research and Monitoring Project
Active
By California Water Science Center
August 3, 2020
Since 1969, the U.S. Geological Survey has maintained a research project in the San Francisco Bay-Delta system to measure and understand how estuarine systems and tidal river deltas function and change in response to hydro-climatic variability and human activities.
Project Overview
Estuaries are the interface of rivers, ocean, atmosphere, and dense human settlement. As such, their variability is driven by a large array of natural and anthropogenic forces. This website describes the long-term research and observation project in the San Francisco Bay-Delta that serves to measure and understand changes in water quality due to these forces.
For the past five decades, the USGS has conducted ship-based measurements of water quality along a 145-kilometer-deep water transect that spans the length of the entire system from ocean to inland delta. We sample the full salinity gradient on monthly cruises aboard the R/V Peterson and historically on the R/V Polaris. Read more about where and when we collect measurements.
We measure the basic elements of water quality that define the sustainability of the Bay as habitat for fish and organisms of the lower trophic levels. Using both oceanographic sensors and discrete water collection, we measure salinity, temperature, light extinction coefficient, chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate, and phosphate. Take a closer look at what we measure and how our measurements are made.
Data availability
Access the Water Quality of San Francisco Bay Data Query to download measurements from 1969 to our most recent cruise.
These publicly available data are used to measure, model, and understand how estuaries function as transitional ecosystems between land and sea where seawater and freshwater meet. We provide examples of the diversity of applications of these data used in many different disciplines that range from tidal circulation and transport processes and sediment-water nutrient exchange, to phytoplankton productivity and responses to climate variability.
Data visualizations for each cruise will be added to this site in the near future.
Science Communications
- Patterns and Processes of Change Where Rivers Meet Oceans: presentation by James Cloern for Moss Landing Marine Laboratories, 2021.
- Chasing the Spring Phytoplankton Bloom: presentation by Tara Schraga at the Exploratorium museum, 2021.
- USGS R/V Polaris Retires: We reflect on what she taught us: poster, 2016.
- How is San Francisco Bay Doing?: presentation by James Cloern for the USGS Public Lecture Series, 2011.
- Four Decades of Water Quality Research in San Francisco Bay: poster, 2009.
- Inside the Golden Gate: Part 1 and Part 2: NOVA television special, filmed aboard the R/V Polaris in 1976
Our Science in the News
- Feel Like the SF Bay Used to Be Bluer? You're Not Imagining It: KQED Podcast and Article, 2019.
- Public radio KALW show, 2016.
- Bay Belle Retires; Catamaran Carries On. Estuary News, 2016.
- Monitoring San Francisco Bay water critical for future. ABC13 News, 2014.
- San Francisco Bay waters are becoming clearer, but that may mean threats from algal growth. San Jose Mercury News, 2013.
- Climate change may transform California's Bay Area. Scientific American, 2011.
Agencies Supporting the Program of Water-Quality Data Collection and Dissemination
- U.S. Geological Survey Water Resources Division (2017 to present), National Research Program (until 2017)
- U.S. Geological Survey San Francisco Bay Priority Landscapes Program
- U.S. Geological Survey California Water Science Center
- San Francisco Estuary Institute: The Regional Monitoring Program
- San Francisco Estuary Institute: San Francisco Bay Nutrient Management Strategy
This work complements the Interagency Ecological Program for the San Francisco Bay/Delta Ecosystem.
Below are other science pages associated with the Water Quality of San Francisco Bay project.
Sampling Locations for the Water Quality of San Francisco Bay Project
Since 1969, the Water Quality of San Francisco Bay Research and Monitoring Project has conducted water-column sampling along the deep channel of the San Francisco Bay-Delta system. Learn more about when and where we collect data.
Sampling Methods for the Water Quality of San Francisco Bay Project
The Water Quality of San Francisco Bay Research and Monitoring Project measures changes in water quality along the deep channel of the San Francisco Bay-Delta system using submersible sensors and discrete water samples. Learn more about how we collect and measure water-quality data.
Research Vessel David H. Peterson
The Research Vessel David H. Peterson begain service with the U.S. Geological Survey in 2015. Named after a founder of the Water Quality of San Francisco Bay Research and Monitoring Project, this vessel is a high-tech scientific platform for estuarine research. Learn more about how the R/V David H. Peterson makes our research possible.
Below are multimedia items associated with the Water Quality of San Francisco Bay project.
PubTalk 7/2011 — How is San Francisco Bay Doing?
discoveries from 4 decades of studies
by Jim Cloern, Senior Research Biologist
Delta Science: Excerpt from “Delta Revival”
"Delta Science" is an excerpt from the USGS produced television program “Delta Revival: Restoring a California Ecosystem”. A link to the complete program follows this description.
"Delta Science" is an excerpt from the USGS produced television program “Delta Revival: Restoring a California Ecosystem”. A link to the complete program follows this description.
Below are other science pages associated with the Water Quality of San Francisco Bay project.
Sampling Locations for the Water Quality of San Francisco Bay Project
Since 1969, the Water Quality of San Francisco Bay Research and Monitoring Project has conducted water-column sampling along the deep channel of the San Francisco Bay-Delta system. Learn more about when and where we collect data.
Sampling Methods for the Water Quality of San Francisco Bay Project
The Water Quality of San Francisco Bay Research and Monitoring Project measures changes in water quality along the deep channel of the San Francisco Bay-Delta system using submersible sensors and discrete water samples. Learn more about how we collect and measure water-quality data.
Research Vessel David H. Peterson
The Research Vessel David H. Peterson begain service with the U.S. Geological Survey in 2015. Named after a founder of the Water Quality of San Francisco Bay Research and Monitoring Project, this vessel is a high-tech scientific platform for estuarine research. Learn more about how the R/V David H. Peterson makes our research possible.
Below are multimedia items associated with the Water Quality of San Francisco Bay project.
PubTalk 7/2011 — How is San Francisco Bay Doing?
discoveries from 4 decades of studies
by Jim Cloern, Senior Research Biologist
discoveries from 4 decades of studies
by Jim Cloern, Senior Research Biologist
Delta Science: Excerpt from “Delta Revival”
"Delta Science" is an excerpt from the USGS produced television program “Delta Revival: Restoring a California Ecosystem”. A link to the complete program follows this description.
"Delta Science" is an excerpt from the USGS produced television program “Delta Revival: Restoring a California Ecosystem”. A link to the complete program follows this description.