The U.S. Bureau of Reclamation will release less water from Nimbus Dam to the lower American River due to the dry winter conditions.
Flows in the river will go from 1100 cubic feet per second down to 500 cubic feet per second by Friday. The Bureau says the reduction is needed to protect fish and drinking water behind Folsom Dam.
The water content of the Sierra snowpack is about 20 percent of average for this time of year. California estimates it will only be able to deliver 5 percent of the water requested by 29 public agencies this year.
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.
The second measurement this winter of snowpack in the Sierra Nevada was 130 percent of average. State water officials say the snowpack will help reservoir recovery.