Klamath River Flow and Water Temperature, Water Year 2012

Water temperature was monitored at several locations in the Klamath Basin from April to October 2012. The uppermost Klamath River site was located upstream of Copco 1 Reservoir on the mainstem Klamath River, and the lowermost site was established just upstream of the Klamath Estuary near Klamath, CA. The highest daily mean water temperature recorded on the mainstem Klamath during the period of study was 24.6°C at Happy Camp, CA on August 5 and 17. Of three tributaries sampled, the Shasta River recorded the highest daily mean water temperature at 26.0°C, but only had a slight influence on mainstem water temperatures due to its low relative volume. Mainstem water temperatures peaked about two weeks later than the past 10-yr mean (2002-2011). Augmented flow releases from Lewiston Dam on the Trinity River were used to reduce risk of a potential fish kill in the lower Klamath River and significantly reduced Klamath River water temperatures during implementation.