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Steelhead Regional Temperature Study

Juvenile O. mykiss on Coyote Creek
Juvenile O. mykiss on Coyote Creek.

Valley Water, in collaboration with the San Francisco Bay Regional Water Quality Control Board, is conducting a Regional Temperature Study to analyze available data, identify data gaps, and develop scientific studies that can be used to refine protective temperature evaluation guidelines to support cold freshwater, migration, fish spawning, and related beneficial uses of Central California Coast (CCC) steelhead (Oncorhynchus mykiss).

The Regional Temperature Study will be conducted in two phases. In the first phase, existing data from the CCC steelhead range will be analyzed to determine the relationship between stream temperature and CCC steelhead occurrence. In the second phase, a research plan will be designed by the Technical Review Panel, an impartial panel of scientists which the San Francisco Estuary Institute facilitates, to refine regionally appropriate temperature evaluation guidelines for CCC steelhead. The research plan may include evaluating historical water temperatures, conducting field studies, and/or conducting streamside experimental or laboratory studies. Such studies could be conducted in the future, after the completion of Phase 2, in partnership with other regional stakeholders.

The CCC Steelhead Regional Temperature Study Work Plan was prepared to facilitate coordination between Valley Water and the Regional Water Quality Control Board and outline a path by which regionally appropriate temperature evaluation guidelines applicable to waterbodies supporting CCC steelhead may be best developed. Staff from the National Marine Fisheries Service, California Department of Fish and Wildlife, and Environmental Protection Agency are providing input on the study.

Presentations and Technical Review Panel Meeting Materials 

O. mykiss juvenile rearing on Coyote Creek.
O. mykiss juvenile rearing on Coyote Creek.

Regional Temperature Study: Background and Status (presentation)

November 19, 2021
Agenda and meeting notes

March 30, 2022
Agenda and meeting notes


Steelhead and Their Habitat

Steelhead spend much of their lives in bay and ocean waters, with adults migrating upstream into freshwater when ready to spawn, typically returning to the streams where they were born. Santa Clara County steelhead are winter-run fish, meaning they enter rivers and streams in the winter when flows are naturally high due to rain, allowing passage to upstream spawning sites. Young steelhead remain in their natal streams for up to three years, gaining weight and size before they are large enough to survive in the ocean. 

Through the Fish and Aquatic Habitat Collaborative Effort (FAHCE) program, Valley Water strives to manage certain critical zones of our
streams, such as the reach of Coyote Creek just downstream of Anderson Dam, to stay cool year-round using strategic reservoir releases