Senior Water Rights Curtailed in Delta, San Joaquin & Sacramento Watersheds

From the State Water Resources Control Board:

SWRCB logo water boardsWith drought conditions continuing into the summer months, the State Water Resources Control Board (State Water Board) announced today that there is insufficient water available for senior water right holders with a priority date of 1903 or later in the San Joaquin and Sacramento watersheds and the Delta. The need for further curtailment of more senior rights and curtailments in other watersheds is being assessed weekly.

Notices are being sent to water right holders that direct recipients to stop diversions of water to protect more senior water rights and releases of previously stored water, as required by state law. Diversion of water when water is not available under the right holder’s date of priority is unauthorized and unlawful. Violations are subject to fines up to $1,000 per day and $2,500 per acre-foot of water unlawfully diverted, cease and desist orders, or prosecution in court.

Senior water right holders with priority dates earlier than 1903 in the affected watersheds can continue to divert water in accordance with their water right. In addition, those who have previously stored water under a valid right may continue to hold that water or release it for beneficial use.

While this is the first time during the current drought that senior water right holders have been given notice that water is not available to serve their water right priority, it is not unprecedented. Some senior water right holders were curtailed during the drought of the late 1970s.

Water Rights Affected by This Notice

Today’s curtailment notices affect 276 pre-1914 appropriative water rights held by 114 right holders. Today’s notices do not affect any riparian right holders. The water rights affected include:

  • On the Sacramento River, 127 water rights with a priority date of 1903 or later are curtailed, affecting water rights held by 86 right holders.
  • On the San Joaquin River, 24 water rights with a priority date of 1903 or later are curtailed, affecting water rights held by 14 right holders.
  • In the Delta, 125 water rights with a priority date of 1903 or later are curtailed, affecting water rights held by 14 right holders.

Uses To be Curtailed

The following uses are listed for the pre-1914 water rights affected by today’s notices:

  • 135 water rights held by 53 right holders for irrigation, stockwatering, and/or livestock as the sole water use; and
  • 208 water rights held by 80 right holders for irrigation, stockwatering, or livestock as at least one of the claimed water uses.

Today’s action is based on reported diversion demands, estimates of natural flows and actual stream flows. Conditions in these and other watersheds continue to be monitored, and curtailment notices for other watersheds and for more senior water right holders in these watersheds may be imminent.

Some water right holders may have other, more senior rights to fall back on, or have water stored in reservoirs that they can still access. If that’s not available they will have to find other sources of water, such as groundwater or purchased water, if available. Water right holders are cautioned that groundwater resources are significantly depleted in some areas.


California water rights law is based on seniority. In dry years, when there isn’t enough water in the system to serve all water right holders, those with more junior rights are required to stop diverting water from rivers and streams before restrictions are imposed on more senior right holders. The Water Commission Act of 1913, which took effect in 1914, created California’s system of water rights and the distinction between junior and senior appropriative water rights.

Senior water right holders are those claiming appropriative water rights established prior to the Water Commission Act, and riparian water rights. Riparian water rights are rights granted to owners of land abutting a stream or river. In most instances, riparian rights share equal priority to the available natural flow and have seniority over appropriative water rights (both pre-1914 and post-1914).  For appropriative rights, the priority system is based on the concept of “first in time, first in right.”

The State Water Board administers California’s system of water rights and is authorized to prevent illegal diversions of water. Illegal diversions include taking water at times when there is insufficient water available under the priority of right held by the diverter.

The State Water Board issued two letters earlier this year warning all water-right holders that their rights may be curtailed due to drought conditions. Last year, the State Water Board issued curtailment notices to more than 5,000 diverters on five watersheds statewide.

In April and early May of this year, the State Water Board issued curtailment notices for all post-1914 water rights in the Sacramento and San Joaquin River watersheds and the Delta.  Curtailment notices were issued in the Scott River and Deer Creek watersheds as well.

In addition, the State Water Board approved a proposal from riparian water right holders in the Sacramento-San Joaquin River Delta on May 22 to voluntarily cut back water use in exchange for assurances that they would not face enforcement actions in the event that their riparian water rights are curtailed more severely later during the June-September growing season.  Riparian water right holders had until June 1 to elect to participate in the voluntary program.

The senior water rights affected by today’s notice add to the growing number of water rights restricted by the State’s ongoing drought as demand far outstrips supply in key Northern California watersheds. As of this notice, a total of 8,721 junior water rights and 276 senior water rights in the Sacramento-San Joaquin River watersheds and Delta have been notified that there is insufficient water in the system to serve their rights.

To determine the need for curtailments, the State Water Board uses monthly diversion data and sorts that data by watershed, water right type and priority date. Water flow used for power generation that is diverted and returned back to the water course is removed from the analysis.  The demands for water use by type of right are summed and plotted graphically to display junior and senior water right needs. To assess supply, monthly and daily natural flow data from the Department of Water Resources (DWR) are plotted with DWR estimates of return flows and additional minor tributary flows. The resulting Supply vs. Demand Curve indicates curtailment is needed when demand outstrips supply.

For this curtailment, several scenarios of delta and tributary demand were analyzed to produce conservative curtailment priority dates. As supplies continue to decline through the summer, it is expected that more senior rights will be subject to curtailment. As supply increases in the fall or winter, the State Water Board will lift the curtailment as soon as appropriate using the same procedure.

The State Water Board maintains a webpage to assist water right holders in several key watersheds to plan for possible limits on water supply availability. The webpage, titled “Watershed Analysis,” details projected water supply, demand and availability for the watersheds most likely to face restrictions during the drought as demand outstrips available water supply.

A Curtailment Fact Sheet provides additional details on the curtailment process. Please visit our curtailment notification website to see what watersheds have received curtailment letters.

Information on the drought is available at the State Water Board’s drought website.

To learn about all actions the state has taken to manage our water resources and cope with the impacts of the drought, visit Drought.CA.Gov.  Every Californian should take steps to conserve water. Find out how at





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