Document Details Page

Search TRRP online library of documents and data

ID: 2601

Buxton, T. H. 2023. Trinity River water allocation, temperatures, and model results for implemented flows and approved hydrographs for water year 2022. Report TRRP-2023-1 for the Trinity River Restoration Program (TRRP). TRRP, Weaverville, California. Available:

Water year (WY) 2022 was critically dry based on the April 1st B120 report that projected full natural flow (FNF) at Lewiston would be 485,000 acre feet (AF). This projection was 4.7% lower than the observed FNF of 507,674 AF. The critically dry WY projection enabled 369,000 AF of water to be released from Lewiston Dam to the Trinity River for river restoration. The actual volume released for restoration (364,809 AF) was 1.1% lower than the allocated volume and within the assumed error range of the flow gage at Lewiston (±10%), indicating the allocated and released water volumes were functionally equivalent. In additional to restoration flows, 27,431 AF was released to help ameliorate temperature impacts on Chinook Salmon in the lower Klamath River. Water exported from the Trinity River basin to the Central Valley was 252,151 AF, which is the lowest diversion volume since 2001 and 36% less water than was released to the Trinity River for restoration. The volume of water stored in Trinity reservoir decreased from 706,800 AF at the start of the water year (10/1/2021) to 553,200 AF at the end of the water year (9/30/2022). This decrease lowered the water surface in the reservoir 24.0 ft and caused the Cedar Stock, Trinity Center, Fairview, Clark Spring, and Stuart Fork boat ramps to remain dry this water year. Water temperatures recommended at Lewiston for aiding salmonid spawning and egg incubation were not met for 28% of the target period. Water temperatures at Douglas City and above the North Fork Trinity River (TRNF) exceeded their compliance values for 76% and 8% of their respective periods. Recommended water temperatures at TRNF for aiding juvenile salmonid rearing were met for 23 days of the 120-day target period in WY 2022. 

First Posted: 2023-03-13 15:32:23

Post Updated: 2023-03-13 15:36:21