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.
A new study says California's four-year drought has reduced hydroelectricity generation, resulting in higher electricity costs to ratepayers and increased greenhouse gas pollution.
Legislation introduced in the California state Assembly would create the Lower American River Conservancy to improve, protect, preserve and possibly expand the 5,000-acre American River Parkway.
January brought above-average rainfall and snow to much of California, partly due to El Niño. But forecasters say the ocean warming condition is "taking a break" for the next week or longer.
The U.S. Drought Monitor says, other than a slight reduction in exceptional drought in the northern Sierra, it needs more time to assess impacts of the recent moisture on California's long-term drought.
California regulators have made modest adjustments to water conservation requirements for cities.