Stream Gaging Plan

Senate Bill No. 19 – Stream Gaging Plan

If you missed the SB 19 Stream Gaging Plan public outreach meeting on February 4, 2021, the recording is now available on YouTube! The link is available in the Outreach tab below.

It is the state’s responsibility to manage and protect California’s water while also protecting, restoring, and enhancing the natural and human environment. A robust stream gage network is essential for effective water management, especially during times of extreme water shortage or flooding. Almost three-quarters of California watersheds do not have a federally or state-operated streamflow gage and the majority (~85 percent) of these ungaged watersheds have surface water diversions. The existing gage network is insufficient to address key management needs (e.g., water supply management, flood management, water quality management, and ecosystem management).

As California learned in the recent drought, the decommissioning of gages and lack of gages in priority watersheds cause significant data gaps that hamper effective management of water resources. State agencies are forced to spend extra resources on field investigations and other less accurate means to obtain the needed data, or to forgo timely and effective action because data are not available. Lack of streamflow information impacts the state’s ability to make the most efficient and effective water management decisions, especially during critically dry periods when limited water supplies must be managed to meet multiple needs such as the protection of senior water rights, water transfers, and protection of threatened and endangered aquatic species.

The state recognizes the importance of stream gaging information. A robust and reliable stream gage network can help state, federal, and local agencies manage water resources and conserve freshwater species more effectively for multiple benefits and help to avoid conflicts.

Senate Bill No. 19 (SB 19) (Statutes of 2019, Chapter 361, Dodd) enacts Water Code section 144, which directs the Department of Water Resources (DWR) and the State Water Resources Control Board (State Water Board) to develop a plan to address gaging information gaps through the deployment of a network of prioritized stream gages in consultation with the California Department of Fish and Wildlife (CDFW), Department of Conservation (DOC), the Central Valley Flood Protection Board (Flood Board), and interested stakeholders. The stream gaging plan will identify significant gaps in the stream gaging network to meet the wide variety of water management needs, which are increasingly important in the face of a changing climate. It is anticipated it will take two years to develop the plan.

The integrated nature of this planning process, with DWR and the State Water Board working in consultation with CDFW, DOC, Flood Board, and interested stakeholders, will strengthen our existing partnerships with other agencies and develop partnerships and relationships among state and local entities and other stakeholders who operate or rely on stream gaging data to manage water in their local watersheds. By working together, a more efficient stream gage network can be designed to meet the State’s key water management needs.

The Governor’s Water Resilience Portfolio recognizes the importance of improving the state’s stream gage network. Action 22.6 of the portfolio states: Build upon implementation of SB 19, which requires an assessment of the state’s stream gage network. Convene state, local, and federal agencies and assess and prioritize the monitoring instrumentation needed (flow meters, remote sensing, weather stations, data logging, wireless transmission, etc.) to support regional resilience.

Per SB 19, the stream gaging plan will include a determination of funding needs and opportunities for modernizing and reactivating existing gages and deploying new gages in priority locations across hydrologic regions in the state. The State Water Board and DWR will develop ranking criteria that will help prioritize gage locations by taking into account the ability to modernize or reactivate stream gages where lack of data contributes to conflicts in water management or where water can be more effectively managed for multiple benefits including water supply, flood, water quality, and ecosystem management. Other criteria to be considered in prioritization and developing the plan include:

  • Opportunities for local agencies to enter cost-share arrangements
  • Ease of integrating the stream gage into the existing network
  • Availability of historic gage data
  • Availability of temperature data
  • Water quality and flow impacts related to cannabis cultivation
  • Integration with the Open and Transparent Water Data Act (Part 4.9 (commencing with Section 12400) of Division 6)
  • Ability to provide data to assist with groundwater management

Development of the plan will include tasks related to researching the existing stream gaging network (locations, costs, funding mechanisms, operational conditions), identifying gaps in stream gaging network, consultation with agencies, outreach with other stakeholders, identifying funding needs for future stream gaging, identification of partnership mechanisms and opportunities for partnering, and development of a draft and final plan.

It should be noted that the plan will identify priority stream gage locations and funding needs to improve the existing stream gage network, but additional funding to install and operate stream gages was not included in the State’s Budget to implement SB 19.

To stay up to date on the process of SB 19, please click on the email subscription box or contact one of the SB 19 team members.

Technical Advisory Committee Participant Representative
Association of California Water Agencies Marc VanCamp
California State Association of Counties Catherine Freeman
California Water Data Consortium Tara Moran
Central Valley Flood Protection Board Doug Kennedy
Internet of Water Peter Colohan
National Oceanic and Atmospheric Administration - California Nevada River Forecast Center Alan Haynes
Northern California Water Association David Guy
The Nature Conservancy Kirk Klausmeyer
Trout Unlimited Mia Van Docto
United States Geological Survey - Water Science Center Mark Dickman

California Stream Gages Explorer Tool

To inform the creation of the SB 19 Stream Gaging Plan, the State Water Resources Control Board (State Water Board) is compiling a comprehensive, geospatial list of long-term stream gages whose data is publicly available. Initially, the list will consist of gages found on the U.S. Geological Survey's National Water Information System (NWIS) and the Department of Water Resources' California Data Exchange Center (CDEC). Over time, stream gages whose data is maintained by other entities may be added. 

Stream Gages Explorer Tool screenshot

The State Water Board also created the California Stream Gages Explorer Mapping Tool, an interactive web map, to allow interested parties to explore the list of stream gages in a map-based format.  Those with an interest in the Stream Gaging Plan process, or just an interest in the state's current gaging network, are encouraged to click the link to explore the map.

Once the map loads, visitors may find it useful to start by clicking on the "Helpful Info" button  near the top of the map pane.  Also, be sure to check back in the future, as additional gage points may be added as they become known.

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General Inquiries or Comments:

For agency specific questions:

State Water Resources Control Board
Dan Schultz at

Department of Water Resources
Teresa Connor at

California Department of Fish and Wildlife
Todd Carlin at

Department of Conservation
Mike Fuller at