Our Critical Low Flow Plan coordinates voluntary agreements with water rights holders in advance of drought, to keep fish alive and conflict to a minimum.

"Critical low flows" occur when low streamflows coincide with critical migratory periods for Endangered Species Act (ESA) listed steelhead and bull trout, as well as reintroduced spring Chinook. In keeping these fish alive and moving to where they need to go, the Partnership aims to reduce conflict and protect the local economy.

The key to the Critical Low Flow program is the establishment of advance, voluntary agreements with water users to leave some of their water instream for short periods of time (typically 10 days or less) during critical low flow years. Individual water users and irrigation districts can use these agreements as a way to demonstrate cooperation in endangered species management efforts. Such agreements are adaptive to the needs of the individual water user and take two main forms:

  1. Option Contracts... Advance agreements made between the Partnership and water right holders that offer a payment to bypass water, switch from surface water diversions to wells, or relocate a surface water diversions downstream of a passage barrier, only when critical low flow conditions are triggered in spring and fall months. The ideal option contract candidate is one that has historically been able to irrigate reliably in the spring and fall. The payment and conditions are negotiated individually with each prospective participant.

  2. Agreements Not to Divert (ANTDs)... Agreements made between the Partnership and relatively junior water rights holders to leave water instream upon Partnership request. The specific quantities to be left instream and the maximum duration are negotiated with each prospective participant.

View the complete Critical Low Flow Plan here.

Please contact Partnership Staff if you are considering participation in the Critical Low Flow Plan.