That's because of an arrangement between recreational companies and the Sacramento Municipal Utility District.
SMUD has agreed to release water flows for hydro-electric generation at times when rafters are out on the water, primarily on the weekends.
Scott Armstrong owns All-Outdoors California Whitewater Rafting.
On Capital Public Radio's Insight today, Armstrong said weekday rafting could be a little too calm...
"...There will be water on weekends, there'll be water at good flows. It'll be a little bit less than it has been in the last couple of years. But because of the agreement and because of what SMUD has to release anyway for hydro-power, we will have good recreational flows."
~Scott Armstrong, All-Outdoors California Whitewater Rafting
Armstrong predicts flows will be strongest from mid-June through Labor Day Weekend.
UPDATE June 26: Fire managers says the Erskine Fire near Lake Isabella in Kern County has grown to 36,810 acres and is 10 percent contained. Two people have died, at least 150 structures have been destroyed and an additional 75 damaged.
Four consecutive years of drought, millions of dead trees and summer heat, are all factors as thousands of firefighters work to control wildfires in California.
Not much change is expected in drought conditions in California during the summer "dry season" but wildfire danger is increasing, with 66 million dead trees in the Sierra Nevada adding potential fuel.
The U.S. Forest Service says 66 million trees are dead in the Sierra Nevada after four consecutive years of drought in California and a bark beetle infestation.
California is in the fifth consecutive year of drought and water providers continue to urge voluntary conservation, as mandatory statewide rules have ended. Sacramento-area residents reduced their water use by 31 percent in May.