Jump to Content  

With the joint support and funding from the Santa Monica Mountains Conservancy, City of Los Angeles Sanitation and Department of Water and Power (LADWP), and anticipated funding from California Department of Fish and Wildlife (CDFW), this project will complete the California Environmental Flow Framework (CEFF) management decision-making process for the Los Angeles River. This analysis will be essential to inform the State Water Board’s decisions on the potential cumulative impacts on critical species and their habitats from requested and anticipated future requests for flow reduction.


The CEFF was developed on behalf of the State Water Board to help managers develop scientifically defensible environmental flow recommendations that can balance human and ecological needs for water. It comprises three “Sections,” which sequentially identify ecological flow criteria for the subject river (Section A), develop ecological flow criteria that accommodate actual constraints (Section B), and reconcile ecological flow criteria with non-ecological management objectives to create flow recommendations, via a Technical Working Group (TWG) process (Section C). Since Sept. 2022, SMMC/MRCA funding has allowed Stillwater Sciences to complete Section A for the mainstem LA River. Work on CEFF Section B and C has now begun, together with discussions among all key agency, public, and tribal interested parties to raise awareness and support for this process.

The L.A. River connects the Pacific Ocean to tributaries, providing a migratory pathway for listed fish, birds, and wildlife with perennial flow supporting critical habitats that are increasingly rare. Their common denominator is flow, an attribute of the River increasingly threatened by stormwater and water-reclamation projects. The project goals are worthy—improve water-supply resiliency—but without systematic evaluation of tradeoffs between ecological and non-ecological goals, the outcome of a piecemeal review of individual projects will result in substantial losses to species, habitats, and recreational opportunities that are presently being supported in many reaches of the L.A. River.

CEFF was developed as a roadmap for reconciling these seemingly competing and uncoordinated interests. It combines a strong technical approach (Sections A and B) with a collaborative TWG stakeholder process (Section C) to reach a workable, consensus conclusion for flow management. Only a multidimensional decision-support process could manage the complexities presented by this setting; and only CEFF has the explicit support of the ultimate decision-making body for flows in the L.A. River.

Our expected outcome from the TWG is a fully framed set of recommendations to guide the State Water Board’s pending and anticipated decisions on multiple flow-modifying. The project will present a range of credible management alternatives, with a transparent analysis of the tradeoffs being made in support of each.


Technical Reports & Documents