2025 Recommended Changes to Environmental Flow

In September the Trinity Management Council voted to approve adaptive changes to ecological water releases from Lewiston Dam into the Trinity River. The recommendation has been sent to the Secretary of the United States Department of the Interior for final approval. The Council approved a collaborative proposal developed between the Trinity River Restoration Program’s Flow Workgroup and representatives of Trinity County. The vote recommends a synchronized flow release and an increase to wet-season baseflows by using existing water allocations designated to the Trinity River for ecological purposes.

The approved recommendation encompasses functional management, a strategy that combines recreational and ecological objectives with the end goal of improving habitat conditions for juvenile anadromous fish, like salmon and steelhead. At the preceding Trinity Management Council quarterly meeting in June, directive was given to the Trinity River Restoration Program’s Flow Workgroup to advance a collaborative proposal with program partners. From June to early September program partners came to agreement and then presented the proposal to the council mid-September. The proposal passed for recommendation to the Department of the Interior with 7 in favor and 1 opposed. Council membership includes the Bureau of Reclamation, the Fish and Wildlife Service, Hoopa Valley Tribe, Yurok Tribe, California’s Natural Resources Agency, National Marine Fisheries Service, the United States Forest Service and Trinity County.

Recommended water year 2025 environmental flow management timeline.

There are two recommended additions to past practiced restoration flow releases

Synchronized Flow Period (December 15 – February 15)

One potential synchronized dam release during a specific period that is determined (or triggered) by a winter storm event with a maximum of 10 boat fishable days lost due to dam releases.

The purpose of a synchronized flow action is to use flows to maintain and form river complexity. In addition to provide ecologically beneficial timing of riverbed turnover, by combining dam releases with a storm event, flows aim to reduce the impact of sedimentation on salmon redds deposited from tributaries like Deadwood Creek.

Wet-Season Baseflow Period (February 16 – April 15)

An increase to prescribed Record of Decision dam releases during a specific period determined by a conservative monthly inflow projection for Trinity Reservoir from the California Department of Water Resources (90% B120).

The purpose of adaptively managing river flows is to increase available food sources and habitat for juvenile salmonids while rearing (growing) in freshwater, prior to their migration to the ocean.

Snow Melt Peak and Recession Period (April 16 – variable)

In April, the Program plans to implement spring snow melt releases with remaining available water based on the California Department of Water Resources April 2025 water year determination.

Ways to Stay Informed

If changes are approved by the Department of the Interior, the Trinity River Restoration Program will announce details regarding; flow action changes, ways to stay informed and notification timelines as they develop.

If you have questions, please contact the Trinity River Restoration Program office at 530/623-1800 or by emailing your question to info@trrp.net.

Realtime Flow Chart

Most data shown here are from the USGS via the waterservices site, plus the USBR and CDWR via the California Data Exchange. Data are provisional and may be recalculated before final approval. The TRRP site checks for new sub-daily values every 15 minutes and for new daily values twice per day. Note that “Full Natural Flow” is an automated estimate from CDWR of the flow that would naturally pass the Trinity Dam site if unimpeded – it is very sensitive to small variations in lake level measurements that may result in negative values when flows would naturally be low, but is more useful for storm events, snowmelt, and averages over longer times. The graphic for water released to the Trinity River versus the water diverted to the Central Valley tends to show higher values for the river ​until summer, when water exports ​to the Central Valley ​typically increase. Click here for a summary of Trinity River flow volumes.


Parameter
Linked to TRRP data viewer
Location
Linked to TRRP online map
Time
Measured
Value
Linked to Source Website
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Online Flow Data