Term 91 Curtailment Information

Term 91 has been included in permits and licenses, granted after 1965, for diversion and use of water in the Delta watershed. Term 91 requires that those holding such permits and licenses cease diverting water when the State Water Resources Control Board’s Division of Water Rights (Division) gives notice that water is not available for use under those permits and licenses. This occurs at times when the State Water Project and Central Valley Project are releasing previously stored water to meet water quality and flow requirements in the Delta and the Delta is termed to be in “balanced conditions,” generally during the summer and fall. The Division will also give notice when Term 91 is no longer in effect.  

Term 91 specifically states: No diversion is authorized by this license when satisfaction of inbasin entitlements requires release of supplemental Project water by the Central Valley Project or the State Water Project.

A. Inbasin entitlements are defined as all rights to divert water from streams tributary to the Sacramento-San Joaquin Delta or the Delta for use within the respective basins of origin or the Legal Delta, unavoidable natural requirements for riparian habitat and conveyance losses, and flows required by the State Water Board for maintenance of water quality and fish and wildlife.  Export diversions and Project carriage water are specifically excluded from the definition of inbasin entitlements.

B. Supplemental Project water is defined as water imported to the basin by the projects, and water released from Project storage, which is in excess of export diversions, Project carriage water, and Project inbasin deliveries.

The State Water Board shall notify the licensee of curtailment of diversion under this term after it finds that supplemental Project water has been released or will be released.  The State Water Board will advise the licensee of the probability of imminent curtailment of diversion as far in advance as practicable based on anticipated requirements for supplemental Project water provided by the Project operators.

Additional information related to Term 91 is available at the following link along with a graph depicting current conditions related to Term 91: 2023 Term 91 Information and Graph.

Additional Information:
U.S. Bureau of Reclamation Term 91 Calculations
Prior Water Year Term 91 Curtailment Graphs: 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015
Frequently Asked Questions (FAQ) (updated November 30, 2018)

Term 91 Curtailment Notices

Questions about these Notices?

• Please contact the staff at Bay-Delta@waterboards.ca.gov