Functional Flows

The CDFW Instream Flow Program has initiated the implementation of the objectives described in Section 9 of the link opens in new windowWater Resilience Portfolio by supporting rapid flow assessment methodologies to develop regional functional flow criteria through the link opens in new windowCalifornia Environmental Flows Framework (PDF) (CEFF). A primary goal of CEFF is to provide a consistent and defensible approach to identifying ecological flow needs for California's rivers and streams. CEFF ecological flow criteria can be refined for regional needs to generate flow recommendations protective of fish and wildlife by sustaining important aquatic and riparian ecosystems.

We are applying CEFF concepts to develop instream flow criteria for watersheds throughout the state in a series of “Instream Flow Regime Criteria on a Watershed Scale” reports (Watershed Criteria Reports). link opens in new windowWatershed flow criteria (PDF) are developed using existing hydrologic and modeling tools that estimate natural monthly flows and a broad array of functional flow components needed for ecosystem structure and function. Functional flows identify the key elements of the flow regime, such as fall pulse flows, wet-season baseflows, peak magnitude flows, spring recession flows, and dry season baseflows.


Background and section-by-section explanations relevant to all Watershed Criteria Reports are described in the Overview document.

Watershed Criteria Reports:

Reviewing the Overview document is essential to understanding the results of the analyses and the flow regime criteria contained in these Watershed Criteria Reports.

Reports are best viewed in the Chrome browser, or downloaded using Firefox or Chrome.