As seen through their plethora of biodiversity, these ecosystems need to be conserved. Scientists, politicians, lawyers, and citizens work together to develop management plans to preserve riparian ecosystems and manage water flow. Below are a few agencies working on these projects.
California's favorite whitewater river can be looked upon as a standard for conservation techniques. They implement stewardship, education, and conservation programs to the public to enhance people's perception of the riparian ecosystem. They've been able to stop dam projects such as the Auburn Dam. See how else they've managed to protect this treasured landmark: https://www.theamericanriver.com/rivers/conservation/
The California Rivers Assessment (CARA) is a computer-based data management system created by UC Davis designed to give resource managers, policy-makers, landowners, scientists and interested citizens rapid access to essential information and tools with which to make sound decisions about the conservation and use of California's rivers.
Buying bonds will allow state government agencies to use the incoming funds to preserve natural reserves. These bonds would fund agencies like the Department of Fish and Wildlife, Department of Water Resources, and State Coastal Conservancy.
Below is a link to bonds relating to protection of Rivers, Lakes and Streams:
Heal the Bay offers plenty of volunteer opportunities relating to cleaning up the L.A. River, surrounding tributaries as well as the local L.A. Beaches.
This organization works across the country revitalizing the riparian ecosystems. They organize large clean up events for friends and family. In California, they work on the American River and the L.A. River.
See how you can get involved:
https://www.americanrivers.org/make-an-impact/national-river-cleanup/volunteers/