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SWP O&M Water Quality Monitoring

Water Quality Monitoring

Beginning in 1968, water quality monitoring for the California State Water Project (SWP) has been conducted by the Department of Water Resources (DWR) Division of Operations and Maintenance (O&M), Water Quality Section to monitor eutrophication (an increase in chemical nutrients) in the SWP facilities and salinity for agricultural users. Over time, the SWP water quality program expanded to emphasize parameters of concern for drinking water, recreation, and fish and wildlife purposes.

Today, chemical, physical and biological parameters are routinely monitored throughout the SWP from the Feather River drainage in the north to Lake Perris in the south, including more than 40 +sites and over 200 individual chemicals. Both discrete grab samples and continuous automated station data comprise a comprehensive water quality monitoring program. This extensive water quality monitoring program provides water quality data to:

  • Document spatial and temporal changes in SWP water quality.
  • Plan water treatment operational changes.
  • Identify and respond to toxic substance spills, floods, and other water quality emergencies.
  • Compare SWP water quality to California drinking water standards, contractual requirements with the State Water Contractors under Water Service Provisions - Article 19, or other criteria.

Aquatic Weed and Algae Control in the SWP

DWR applies copper compounds (copper sulfate pentahydrate, Komeen, Nautique, Captain), diquat (Tribune) and endothall (Aquathol K) on an as-needed basis to control aquatic weeds and algal blooms in SWP water. These applications are necessary so that aquatic weed growth and algal blooms do not degrade drinking water quality through elevated tastes and odors, production of algal toxins, clogging of filters, and reduction in water flows. DWR’s Aquatic Pesticides Application Plan describes the department’s aquatic herbicide and algaecide application and monitoring program.

2017 Aquatic Herbicide and Algaecide Applications in the SWP

DWR O&M's application of aquatic herbicides and algaecides for 2017 began on May 10, 2017. South Bay Aqueduct was treated with copper sulfate to control algae. Treatments will continue on an as-needed basis to control algae and aquatic weeds. Public access to SWP water bodies will be restricted during aquatic herbicide treatments.

For more information, please contact Diane Shimizu at (916) 653-1154.