Meeting dissolved oxygen standards reduces stress on aquatic species.

The Measure

Applicable dissolved oxygen (DO) standards in the Delta and Suisun Marsh are consistently met.

  • Expectations

    Applicable dissolved oxygen (DO) standards in the Delta are consistently met.

  • Performance Metrics

    • Milligrams of DO per liter of water (mg/L).
    • Continuous, real-time DO measurements made at multiple locations throughout the Delta.

Number of Days Not Meeting the Objectives for Water Year 2018

This map shows the stations that have missed the minimum target of a daily average of 5 mg/L of dissolved oxygen for water year 2018. Click on the points to view what year and approximately how many days a station missed the target.

Locations of Monitoring Stations

Map of the Delta with Dissolved Oxygen stations
Locations of monitoring stations that record dissolved oxygen at 15-minute intervals in the Delta.

Data used for this performance measure were as of May 2013 or the earliest date the station started collecting data after May 2013. For a full list of stations and water quality data, please visit: DWR's California Data Exchange Center.

The tear drop shaped points (blue) symbolize stations that met the minimum objectives for water year 2018 while the circle points (red) symbolize stations that did not.

Dissolved oxygen water quality objectives ensure aquatic organisms receive minimum dissolved oxygen requirements for optimal growth and life support. Meeting dissolved oxygen water quality standards will help prevent negative effects to wildlife. For example, dissolved oxygen concentrations in the Stockton Deep Water Ship Channel and Old and Middle Rivers can drop to inhospitable conditions during warmer and lower water flow periods. In Suisun Marsh, the decay of plant matter in late summer and early fall causes severe dissolved oxygen depletion. Low concentrations of dissolved oxygen can adversely affect aquatic life, including the health and migration of native fish such as salmon.

Several actions taken to comply with the minimum dissolved oxygen requirements, along with improved water flow and a reduction of pollution loads in the San Joaquin watershed appear to have provided a solution to this water quality problem. Consistently meeting the dissolved oxygen levels above the minimum recommended levels specified in the Sacramento River and San Joaquin River Basins and San Francisco Bay Water Quality Control Plans will benefit the Delta ecosystem by providing optimal living conditions to native aquatic wildlife.

Each chapter of the Delta plan includes strategies to achieve the goals of the plan. These strategies are general guidance on achieving the objective laid out in the plan and in the Delta Reform Act of 2009. Associated with these strategies are recommendations. The recommendations describe more specific and implementable actions to support the achievement of Delta Plan strategies. Strategies and recommendations may also have associated performance measures. Delta Plan performance measures track progress in achieving desired outcomes for the Delta Plan. Below are the strategies and recommendations associated with this performance measure.

Delta Plan Strategy

  • Improve environmental water quality

Delta Plan Recommendations

  • Completion of regulatory processes, research, and monitoring for water quality improvements
  • Implement Delta Regional Monitoring Program
  • Evaluate wastewater recycling, reuse, or treatment
  • Manage dissolved oxygen in Stockton Deep Water Ship Channel
  • Manage dissolved oxygen in Suisun Marsh
  • Milligrams of DO per liter of water (mg/L).
  • Continuous, real-time DO measurements made at multiple locations throughout the Delta.
  • Measured as of the date of the Delta Plan’s adoption, May 2013.
  • Meet water quality objectives for DO in the Stockton Deep Water Ship Channel, Suisun Marsh, and Old and Middle Rivers.
  • Maintain or exceed the minimum DO concentrations of:
    • 5 mg/L daily average everywhere in the Delta.
    • 6 mg/L daily average from September through November in the San Joaquin River between Turner Cut and Stockton.

Dissolved Oxygen (DO) is obtained through DWR's monitoring stations. 15-minute interval data was collected and then used to average daily DO levels. Monitoring data is available through DWR's CDEC website. Suisun Marsh readings were not included since targets for DO targets were only recently approved as of August 2018.

Data Source:
California Data Exchange Center



When using data, please use the original source data. Just like the source data, the data is provisional and is subject to change. Data collected was as of May 2013 or the earliest date the station went online.

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