State Water Project Routine Water Quality Monitoring

The California State Water Project (SWP) is one of the nation’s largest water conveyance projects. Its geographic extent stretches from Sierra Nevada lakes north of Lake Tahoe, down the Central Valley, across several mountain ranges, and through the Mojave Desert, ultimately terminating at four large reservoirs in Southern California. The SWP also supplies water to communities in the northern and southern San Francisco Bay Area and along the Central Coast. In total, the SWP delivers raw drinking water to treatment plants serving over 27 million people, provides irrigation water for more than 750,000 acres of farmland, and supports recreational access at many lakes and reservoirs throughout the state.

The Division of Operations and Maintenance within the Department of Water Resources (DWR) monitors water quality in the SWP at locations strategically situated throughout the Project. The SWP monitoring program began in the early 1960s and continues to this day. The location, frequency, and constituents tested for have changed several times during this period to meet the new and expanding needs of SWP water users. The bulk of samples collected for this monitoring effort have been analyzed by DWR’s internal laboratory, Bryte Lab. Additional tests outside of Bryte Lab’s capability or capacity have been analyzed at non-DWR affiliated laboratories. This dataset covers all samples collected as part of the SWP’s routine water quality monitoring program. This does not include data collected for special projects, specific permit or regulatory requirements, or short-term studies.
The following sections provide more information about specific types and groups of samples and their data analysis and availability.

___Standard Water Quality Analytes:___ This group of data contains the most commonly sampled for analytes and parameters for this program. This includes anions, cations, nutrients, organic carbon, solids, and field measurements such as conductivity, pH, turbidity, and water temperature. These data are analyzed by Bryte Lab and are available on the [Water Data Library](https://wdl.water.ca.gov/waterdatalibrary/).

___Asbestos:___ Samples for asbestos analysis have been collected at a few locations within the SWP since 1980 following detections of asbestos fibers in water delivered from the SWP. Subsequent studies showed several point and non-point sources that may contribute to asbestos in the SWP. The ongoing samples have been analyzed at several different labs during this time. Data from before 2009 have not been compiled into CSV format but are available as laboratory reports. These reports can be obtained by submitting a [record request](https://californiadwr.mycusthelp.com/WEBAPP/_rs/(S(3q2tw3v2guzqsnh1objifgtv))/supporthome.aspx). Data from 2009 and after are available in CSV format in this dataset with the exception of data during 2011-2014 when several reports were lost.

___Organic Chemicals:___ Several different classes of organic chemicals have been a part of the SWP monitoring program for many decades including analysis of phenols from the start of the program. Continued analysis of organic chemicals has included various types of pesticides, herbicides, semi-volatile organic compounds, and volatile organic compounds. The specific list of compounds has changed over time to meet specific program needs and laboratory analytical capabilities. Samples before 2020 were analyzed by Bryte Lab and are available on the [Water Data Library](https://wdl.water.ca.gov/waterdatalibrary/). Samples in 2020 and after were sent to non-DWR affiliated labs and are available in this dataset.

___PFAS:___ Sampling for PFAS in the SWP began in 2020 and has grown in frequency and number of sampling sites. These samples have been analyzed at non-DWR affiliated labs and are available in this dataset.

___Radionuclides:___ Samples for gross alpha, gross beta, Potassium-40, and tritium have been collected since the late 1990s. These samples have been analyzed by the California Department of Public Health’s Drinking Water and Radiation Laboratory. Results prior to 2010 have not been compiled into CSV format but are available as laboratory reports. These reports can be obtained by submitting a [record request](https://californiadwr.mycusthelp.com/WEBAPP/_rs/(S(3q2tw3v2guzqsnh1objifgtv))/supporthome.aspx). Data from 2010 and after are available in CSV format in this dataset.



Suggested Citation: State Water Project Water Quality Program. (n.d.). Routine Water Quality Data. California Department of Water Resources. Retrieved Month Day, Year, from https://data.cnra.ca.gov/dataset/state-water-project-water-quality