Instream Flow Analysis – Santa Maria River

The precipitous decline of salmon and steelhead populations throughout the state of California is attributed to numerous factors, some of which include; water supply, water quality, habitat destruction, and blockages to fish migrations. The instream flow projects are designed to look at one aspect of the myriad of issues plaguing salmon populations, water quantity. There are three instream flow projects the OPC approved statewide, they include; the Shasta River, the Big Sur, and the Santa Marina River.

Each of the rivers were chosen based on a list of twenty-two priority streams that require instream flow analysis throughout the state. (This list is exhibit 2 of the staff recommendation, linked below).

This list was developed with input from regional DFG staff, water board staff, U.S. Fish and Wildlife Service, and NOAA national marine fisheries service.

In developing the list of priority rivers, DFG staff considered criteria such as; 1) presence of anadromous species, 2) likelihood that DFG flow recommendations would provide a high level of improvement, 3) availability of recent flow studies or other relevant data, and 4) the possibility of partners and willing landowners to work with staff on these assessments.

Completion of these projects satisfies many goals and priorities for the OPC, including the goal to significantly improve the quantity and quality of ocean and coastal habitat in California, specifically to work toward monitoring and measuring stream flows on key coastal streams as well as to determine the flow rates necessary to protect water quality in coastal lagoons and estuaries.

OPC funds will be used to conduct a water flow analysis for the entire Santa Maria River. Tasks will include hydrologic and geomorphic data collection and habitat mapping, estuary studies, adult steelhead migration studies and juvenile habitat suitability criteria.  The completion of all the projects will aim to provide an increase in habitat for salmonids.

Events and Updates
Final Report

The OPC authorized $600,000 for the completion of the Santa Maria River instream flow projects.

The Department of Fish and Game
The State Water Resources Control Board
Pacific States Marine Fisheries Commission
Humboldt State University


The research gained from this project will help identify the quantity of water, what temperature, and flow that is required for salmon and steelhead species to properly mature in freshwater environs. The data gathered will hopefully lead to an increase in available habitat and water supply for these endangered species.

The result of the instream flow analysis will be provided to the State Water Resources Control Board by the Department of Fish and Game in the form of flow recommendations for the Santa Maria River.

Council Douments:
Instream Flow Staff Recommendation (June 2010)

Related Projects:
Big Sur Instream Flow Project
Shasta River Instream Flow Project
CEMAR Southern Steelhead Resources Project

Categories: Aquaculture