Blog: Warm water temperature in Lower Sacramento River in May 2024
In the third week of May 2024, the water temperatures in the lower Sacramento River recorded at Wilkins Slough increased to 72oF, well above the 68oF water quality standard (Figure 1). These warm water temperatures occurred in a wet spring of an Above Normal water year that is following a Wet water year. The water temperature spike occurred between prescribed pulse flow releases from Shasta Dam in May (Figure 1). Three pulse flows were prescribed this spring to promote and assist migration of juvenile salmon into the lower Sacramento River and the Delta. After the second pulse in early May, the lower river flow was allowed to drop to a drought-level 5000 cfs, causing the high water temperatures. Shasta Reservoir was virtually full at 4.3 MAF during all of May. The Central Valley Basin Plan’s water quality objective for the lower Sacramento River is 68oF maximum “during periods when temperature increases will be detrimental to the fishery.” (P. 3-14).