The U.S. Bureau of Reclamation has cut water releases from 1,100 cubic feet per second down to 500 feet.
"That has exposed some of the fall run salmon nests or 'redds' as they're called, r-e-d-d."
Tom Ghoring is with the Sacramento Water Forum.
On Capital Public Radio's Insight with Beth Ruyak, Ghoring said early surveys show that reductions, prompted by the dry winter, have left 15 percent of salmon nests or "redds" out of water.
"We know that exposing them is harmful to them. An exposed redd doesn't necessarily kill the eggs buried in the redd, but some of the nearby redds that are still underwater may be harmed so much that they could die."
~Tom Ghoring, Sacramento Water Forum
Reclamation officials say reducing water flows into the American River will help conserve the water supply stored behind Folsom Dam.
Insight will have more about how the lack of rain is impacting the region, coming up at 9 a.m.
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.
As thousands of federal and state firefighters work to contain wildfires in California and other western states, record-setting heat has prompted warnings from the National Weather Service for parts of California, Nevada and Arizona.