UPDATE: October 13 update on curtailment status of water rights and claims in the Delta watershed

From the State Water Resources Control Board:

This update contains important information about the curtailment status of water rights and claims of right within the Sacramento-San Joaquin Delta (Delta) watershedpursuant to orders that were issued on August 20, 2021 (Order for water rights/claims under 5,000 acre-feet and Order for water rights/claims over 5,000 acre-feet).  

October curtailment statuses, which were last updated on October 6, 2021, have been updated today based on recent water supply and precipitation forecasts.  Supply forecasts will continue to be evaluated regularly to determine if further suspensions or re-impositions of curtailments are appropriate, and updates will continue to be provided by email and web posting at least weekly.  Please check the Delta Watershed Curtailment Status List for the current curtailment status of each water right and claim in the Delta watershed.

The following priorities of water rights and claims are curtailed at this time, unless and until the State Water Board advises that this determination has been updated:

1. Water rights and claims on the following San Joaquin River tributaries:
   1. All post-1914 appropriative water rights, pre-1914 appropriative water right claims, and riparian water right claims in the Calaveras River subwatershed that are outside of the Legal Delta;
   2. All post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Merced River subwatershed;
   3. Post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Stanislaus River subwatershed with a priority date of 1850 or later that are outside of the Legal Delta;
   4. Post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Tuolumne River subwatershed with a priority date of 1900 or later;
2. Post-1914 appropriative water rights and pre-1914 appropriative water right claims with a priority date of 1928 or later in all other tributaries of the San Joaquin River watershed that are outside of the Legal Delta;
3. Water rights and claims on the following Sacramento River tributaries:
   1. All post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Yuba River subwatershed;
   2. Post-1914 appropriative water rights and pre-1914 appropriative water right claims in the American River subwatershed above Folsom Reservoir with a priority date of 1852 or later;
   3. Post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Bear River subwatershed with a priority date of 1853 or later;
   4. Post-1914 appropriative water rights and pre-1914 appropriative water right claims in the Cache Creek subwatershed with a priority date of 1859 or later;
   5. Post-1914 appropriative water rights in the Stony Creek subwatershed with a priority date of 1977 or later; and
4. Six post-1914 appropriative water rights associated with the Central Valley Project and State Water Project in the Sacramento River watershed and in the Legal Delta.

For those with limited internet access, a pre-recorded version of the summary above can be heard on the Delta Curtailment Status phone line at (916) 323-4643.

These curtailments are based on water supply forecasts from the California Nevada River Forecast Center (CNRFC) that were updated on October 13, 2021.   To reflect the more dynamic nature of water supply conditions at this time of year, today’s curtailment updates were determined based on an assessment of supply and demand data on a weekly time step, whereas prior assessments were based on a monthly time step.  Supply forecasts factor in anticipated precipitation and water supplies produced by associated runoff in the next seven days, while demand values are computed seven-day averages.  This analysis based on short-term data will help ensure that curtailments can be suspended if forecasted precipitation events are expected to generate sufficient runoff. 

The 50% exceedance water supply forecast was selected to determine curtailments at this time, which will be reassessed next week (or earlier if appropriate) based on daily water supply observations and updated forecasts.  Demand data informing curtailments continue to be based on reported diversions from 2018.  Projected demand data received through Enhanced Reporting Forms are being assessed to determine their potential use for informing future curtailments.

For more information about drought in the Delta watershed, please visit the Delta Drought webpage.  For more information about curtailment compliance and responses to the August 20 Orders, please visit the Curtailment Compliance and Responses webpage.  The Curtailment Compliance and Responses tracker is updated every Friday and can be filtered to see the latest delinquencies.  If you have any questions, you may send an email to Bay-Delta@waterboards.ca.gov or call the Delta Drought phone line at (916) 319-0960.