The Consumnes River is the last undammed river that can be found flowing throughout the Central Valley. With no major dams on its course of 80 miles, it floods after heavy rains, bringing in sediments that provide nutrients for the vegetation, as well as recharging groundwater levels. It originates in the Sierra Nevada and flows through the El Dorado Forest, similar to the Yuba River. This watershed has a beautiful array of landscapes - blue oak, grasslands, redwoods, and rare vernal pools. Land ownership along the Consumnes River Preserve along the lower Cosumnes River at the confluence with the Mokelumne and Sacramento rivers, is divided amongst The Nature Conservancy, US Bureau of Land Management, Ducks Unlimited, California Department of Fish and Wildlife, California Department of Water Resource, and Sacramento County. There are also several different private land owners that use the area for farming. The preserve contains critical floodplain and riparian forest.
The Cosumnes River is included on the federal Clean Water Act list of impaired water bodies due to invasive species, sediment toxicity and pathogen contamination. Fall run Chinook salmon are federally listed as a species of concern. Steelhead are federally listed as threatened. Preventing the extinction of salmon and steelhead requires restoration of priority habitat conditions (listed in the Snapshot Restoration webpage) and consistent, funded monitoring of these fish populations.