About The San Joaquin River

The San Joaquin River originates high in the Sierra Nevada near Yosemite and Kings Canyon National Parks, traveling 330 miles before it reaches the San Francisco Bay Delta. It is the second longest river in California and empties into the largest estuary on the west coast of North America. The San Joaquin River is a source of drinking water for many Californians and provides essential water for wildlife and plants. The River also supplies water to over a million acres of cropland, making it essential to the economic well-being of San Joaquin Valley residents.

The San Joaquin River Valley once supported a highly diverse and species-rich ecosystem. The Valley floor was once a matrix of distinct river and wetland habitats in close proximity to one another. The complex system of river channels, flood basins, and sloughs were seasonally inundated with spring runoff and supported a great diversity of permanent and seasonal wetlands, riparian scrub and forest, and aquatic habitats that teemed with fish and wildlife. The San Joaquin River’s rich and diverse habitats were extremely important for migratory birds traveling along the Pacific Flyway, and tens of millions of migratory waterfowl darkened the skies each winter. Nearly 50,000 acres of riparian forest rich with migratory birds and unique small mammal species flanked the streams and rivers in the basin.

The San Joaquin River is one of the most highly-altered systems in the state. Most of the River’s water is diverted at Friant Dam, leaving stretches of riverbed dry for much of the year. With less than 10% of historic riparian habitat remaining, nearly all of the riparian vegetation has been lost, and wetland habitats have shrunk to roughly 5% of their former extent.