Scott Valley, Siskiyou

Trinity River Spring Flow Pending U.S. Dept. of Interior Approval

Source Trinity River Restoration Program


Current Restoration Flow Release Schedule

B120 forecasts were released by the California Department of Water Resources on February 8 and March 8, 2023. Under TRRP’s Winter Flow Variability plan, this allowed scheduling 60,000 acre feet of release from Lewiston Dam, above the winter base-flow level, for the February 15 – April 15 period, then an additional 60,000 acre feet for the March 15 – April 15 period.

The April B120 forecast was posted April 10, 2023, with an inflow of 1,620,000 acre-feet (50% level), which determined the water-year type for the TRRP volume as “Wet”. The TRRP flow schedule that has been approved by the TMC for a Wet year is still pending final approval by the U.S. Department of Interior. 

This flow schedule includes two peaks at 11,000 cfs from Lewiston Dam within April (although both are so brief that the daily average release will be lower).

An image of the hydrograph is provided below, along with a link to download a flyer that includes the daily-average schedule.

Most data shown here are from the USGS via the waterservices site, plus the USBR and CDWR via the California Data ExchangeData 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.

CDWR Apr. B120 forecast​determines restoration total volume.​




Forecast is released about the 10th.​

Linked to TRRP data viewer
Linked to TRRP online map
Linked to Source Website
FlowTrinity River above Coffee Creek2023-04-11 03:30:00 PDT1430 cfs
Full Natural Flow (estimated daily average)Trinity Dam2023-04-09 (daily)2931 cfs
Diversion Flow (daily average)DIVERSION: To Whiskeytown Lake and the Central Valley, from Lewiston Lake via Clear Creek Tunnels and Carr Powerhouse.2023-04-09 (daily)26 cfs
FlowTrinity River at Lewiston, Gage2023-04-11 03:45:00 PDT3350 cfs
FlowTrinity River below Limekiln Gulch2023-04-11 03:30:00 PDT3440 cfs
FlowTrinity River at Douglas City, Gages2023-04-11 03:00:00 PDT4160 cfs
FlowTrinity River at Junction City2023-04-11 03:45:00 PDT4840 cfs
FlowTrinity River above North Fork Trinity2023-04-11 03:45:00 PDT5470 cfs
FlowTrinity River near Burnt Ranch2023-04-11 03:45:00 PDT8480 cfs
FlowTrinity River at Hoopa2023-04-11 03:00:00 PDT18900 cfs

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