Healthy, flowing rivers create healthy ecosystems that sustain California’s unique plants and wildlife while providing an array of vital benefits to human communities. Whatever you value—nature, recreation, or local life—a river is likely at the heart of it.
Rivers Support—and Connect—Healthy Ecosystems
Black bear foraging at the headwaters during snow pack survey in El Dorado County. Photo Credit: Department of Water Resources
Rivers play a primary role in creating habitat, shaping the landscape, and connecting and supporting living systems. Rain, snowmelt and subsurface flows from aquifers fill rivers with the fresh water that carves river canyons, moves sediment downstream to form wetlands and beaches, transports nutrients and other organic materials to stimulate the food web, cues the migration of fish from and to the ocean, and inundates marshes and floodplains, which in turn store and regulate flows as they move downstream.
Rivers are the essential connectors of life, with salmon, sturgeon and other migratory species creating nutrient flows that bind the terrestrial ecosystem to the marine. Where rivers meet the sea, the back-and-forth interplay between outgoing freshwater river flow and incoming ocean tides forms the heartbeat of California’s estuaries, including the magnificent San Francisco Bay-Delta Estuary.
Before the construction of the massive system of dams and canals that radically altered the natural flow of rivers in California, not only were all these ecosystem services thriving, but rivers were complex systems that shaped the surrounding landscape. Sediment transport and beaver dam-building created islands, complex channels, and back waters. Dense plant life formed thick bands around river levees and vast wetlands filtered the water as it moved through them. Much of this complexity has been reduced by the reduction of river flows, river channelization, and conversion of wetlands and floodplains to other uses.
River ecosystems sustain a rich diversity of California's fish and wildlife
California’s rivers and estuaries are home to many unique and charismatic fish and wildlife species that bring us joy, contribute to healthy ecosystems, and are economically important, from salmon, steelhead, sturgeon and smelt to bears, otters and sandill cranes. Learn more about the unique fish and wildlife species of our rivers.
Rivers provide clean water
Healthy, flowing rivers are the ultimate source of clean drinking water for many communities. They also flush pollution from the system, nourish ecosystem elements like wetlands and shellfish that remove contaminants from the water, and prevent stagnant conditions that promote harmful algal blooms. Discover how healthy rivers keep our water clean and safe.
Rivers Enrich Our Lives—Body and Soul
California rivers, including many popular or iconic whitewater reaches, support thriving commercial and recreational rafting and other river recreation activities that create important local economic benefits and attract recreationists from around the world. These rivers also are the bulwark of many fish species like Chinook salmon and rainbow trout that not only support valuable commercial and recreational fisheries but are also an important food source for subsistence fishers. Rivers are also critical to the religions and belief systems of indigenous peoples and play an important role in cultural and economic practices.
Sadly, California has not protected its rivers the way they deserve. Tens of thousands of dams and diversions block access to spawning grounds for migratory fish, trap sediment needed to nourish rivers, and capture much of the natural river flows for delivery to irrigated agriculture and municipal water use. But rivers are resilient – even dry rivers can be brought back to life! Learn about the ongoing threats to rivers and what Friends of the River is doing to fight them.