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Watershed Opportunities

The last free flowing western Sierra River, the Cosumnes is situated between the American River basin to the north and the Mokelumne River basin to the south. The river flows in a west-southwest direction for over 80 miles, eventually reaching the Delta via its confluence with the Mokelumne River.   


The Cosumnes Watershed is rich in ecological values and productive agricultural lands, worthy of preservation.  Highlights include:


  • Naturally spawning salmon run
  • A part of the Pacific Flyway, the Cosumnes is a nationally significant migratory bird refuge; the Cosumnes Preserve alone is home to over 250 bird species.
  • Largest remaining Central Valley Riparian Forest
  • Abundant threatened Blue Oak Woodland, Mixed hardwood/Conifer, and Red Fir Forests
  • Home to hundreds of special status species
  • If preserved, the mosaic of agricultural and habitat lands along the river corridor will enhance climate resiliency and create a refuge from the expanding northern urban corridor--for both people and creatures.
  • Historical public investment restored thousands of acres of Cosumnes floodplain and wetland habitats that have been studied for decades.  The knowledge gained from Cosumnes research guides restoration efforts around the world.


Uniquely wild and scenic, with Intact geomorphology and winter hydrograph, the Cosumnes offers rare opportunities for restoration and preservation.  

 Cosumnes is a Miwok word, cos=salmon, umne=people, or "salmon people".  The Miwok people have traveled and lived throughout the Cosumnes River watershed for thousands of years.