Term 91 is a provision included in many water permits issued by the State Water Resources Control Board that restricts specified post-1965 permittees from diverting water released by the SWP and the CVP into the Delta when natural and abandoned flows are insufficient to meet water quality standards and the water projects are supplementing flows with previously stored water to meet those standards.
The primary intent of the provision is to ensure that water from the water projects that is being released to meet water quality standards is not diverted for other uses, thereby allowing the water to flow through the Delta to improve water quality.
Term 91 is designed to share the responsibility with specified junior diverters, as without Term 91 conditions, those diverters could take the water being released to meet standards, thereby forcing the Projects to release more water in order to satisfy their obligations to meet water quality standards.