California is one of the most hydrologically altered landscapes in the world. As water becomes ever more scarce and the human population continues to grow, that vast engineered system strains to meet the needs of people let alone the needs of nature. 

Water rights allocations far exceed actual surface water supply, and millions of wells tap groundwater to meet the increasing demands of farms and communities. As groundwater reservoirs are depleted they can in turn reduce surface flows – exacerbating a vicious cycle in which people and nature both lose. Rivers, wetlands and groundwater-dependent ecosystems are caught in this struggle for an increasingly limited resource. Nearly half of California’s roughly 4,000 freshwater species are considered vulnerable to extinction. Of the taxa that are found nowhere but California – our endemic freshwater biodiversity – 90 percent are at risk.

But there is hope. While it is impossible to return natural flows to most of California’s rivers and streams, we can – through science, technology, and innovative market tools – endeavor to deliver water when and where nature needs it most.

Groundwater

In a normal year, groundwater accounts for 40 percent of California’s water supply. That…>>

Surface Flows

Californians have fundamentally altered many of the state’s rivers and streams with dams,…>>

Science in Action

Freshwater | Terrestrial | Science

Rewilding the San Joaquin Valley

40 years of science sets the course for the largest recovery of species in U.S. history

Freshwater | Terrestrial | Marine | Science

Research for Impact

How do we design scientific research to have impact in the world?

2015 | Freshwater | Marine | Publications & Reports

Climate mediates hypoxic stress on fish diversity and nursery function at the land–sea interface

Brent B. Hughes, Matthew D. Levey, Monique C. Fountain, Aaron B. Carlisle, Francisco P. Chavez, Mary G. Gleason

This comprehensive study of a major California estuary documents the links between nutrient runoff from coastal land use, the health of the estuary as a nursery for young fish, and the abundance of…

2015 | Freshwater | Data

Groundwater Dependent Ecosystems in California data

Jeanette Howard, Matt Merrifield

The California Freshwater Species Database is the first comprehensive geospatial database of California’s freshwater species compiled and standardized into single format from nearly 500 sources.…

2015 | Freshwater | Terrestrial | Marine | Planning | Science | Publications & Reports

Recommendations for improving recovery criteria under the US Endangered Species Act

Doak, D.F., G.K. Himes Boor, V.J. Bakker, W.F. Morris, A. Louthan, S.A. Morrison, A. Stanley, L. Crowder

One of the key components of a recovery plan for a threatened or endangered species in the United States is the set of recovery criteria that will be used to evaluate progress in abating the threats…

2014 | Freshwater | Terrestrial | Marine | Planning | Science | Publications & Reports

A framework for conservation in a human-dominated world

Scott Morrison

Recognition of the magnitude of human impacts on the planet and the urgent need to increase the pace and scale of conservation has led many conservation organizations to emphasize conservation for…

2014 | Freshwater | Marine | Planning | Publications & Reports

An Inventory and Classification of U.S. West Coast Estuaries

Walter N. Heady, Kevin O'Connor, Jennifer Kassakian , Kate Doiron, Charles Endris, Daniel Hudgens, Ross P. Clark , Jena Carter , Mary G. Gleason

Estuaries are some of the most productive ecosystems on the planet. This inventory classifies more than 600 coastal confluences on the West Coast of the United States. Each estuary was classified…

2014 | Freshwater | Marine | Science | Publications & Reports

Nursery Functions of U.S. West Coast Estuaries: The State of Knowledge for Juveniles of Focal Invertebrate and Fish Species

Brent B. Hughes, Matthew D. Levey, Jennifer A. Brown, Monique C. Fountain, Aaron B. Carlisle, Steven Y. Litvin, Correigh M. Greene, Walter N. Heady, Mary G. Gleason

Estuaries support significant biodiversity and important ecosystem functions such as providing rearing habitat for juvenile fish and invertebrates. This report synthesizes the scientific…

2014 | Freshwater | Science | Publications & Reports

Low-Cost Restoration Techniques for Rapidly Increasing Wood Cover in Coastal Coho Salmon Streams

Jennifer K. Carah, Christopher C. Blencowe, David W. Wright

Coho salmon in California are critically imperiled so there is strong impetus to achieve as much habitat restoration as possible in priority watersheds quickly and with limited resources. This paper…

2014 | Freshwater | Maps & Webmaps

Hope Runs Deep: Conservation Solutions for Salmon in Shasta Valley

Jeanette Howard, Megan Webb, Katie Andrews

Using maps, images, and video, this interactive StoryMap illustrates how The Nature Conservancy works with partners in Shasta Valley, California to find conservation solutions that work for…

2014 | Freshwater | Publications & Reports

Restoring conservation nodes on the Santa Clara River

Parker, Sophie, Remson, E.J, Verdone, Lily

This paper reviews how the Conservancy has maximized its return on investment on the Santa Clara River in Ventura County, California by focusing riparian restoration efforts in a few…

2013 | Freshwater | Terrestrial | Marine | Planning | Publications & Reports

Biodiversity in a changing climate: a synthesis of current and projected trends in the US

Michelle D Staudinger, Shawn L Carter, Molly S Cross, Natalie S Dubois, J Emmett Duffy, Carolyn Enquist, Roger Griffis, Jessica J Hellmann, Joshua J Lawler, John O'Leary, Scott A Morrison, Lesley Sneddon, Bruce A Stein, Laura M Thompson, Woody Turner

This paper synthesizes research pertaining to climate change impacts on biodiversity, reviewed by the biodiversity technical working group of the 2014 National Climate Assessment. The paper focuses on…

2013 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Successes, Failures and Suggested Future Directions for Ecosystem Restoration of the Middle Sacramento River, CA

Golet G.H., D.L. Brown, M. Carlson, T. Gardali, A. Henderson, K.D. Holl, C.A. Howell, M. Holyoak, J. Hunt, G.M. Kondolf, E.W. Larsen, R.A. Luster, C. McClain, C. Nelson, S. Paine, W. Rainey, Z. Rubin, F. Shilling, J.G. Silveira, H. Swagerty, N.M. Williams, D.M. Wood

Large-scale ecosystem restoration projects seldom undergo comprehensive evaluation to determine project effectiveness. Consequently, there are missed opportunities for learning and strategy…

2013 | Freshwater | Planning | Science | Publications & Reports

Below the Surface: California’s Freshwater Diversity

Jeanette Howard, Kirk Klausmeyer, Kurt Fesenmyer

Californians face profound decisions regarding the management of their state’s increasingly limited water supply. Critical for decision-making is information about the plants and animals that…

2013 | Freshwater | Terrestrial | Science | Publications & Reports

Decline and Recovery of Small Mammals after Flooding: Implications for Pest Management and Floodplain Community Dynamics

Golet G.H., J. Hunt, D. Koenig

Floodplains often are managed both for agriculture and as habitat for native species. On the Sacramento River, farmers have expressed concern that natural areas may be sources of pests to adjoining…

2012 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Restoring Salmon Habitat: Garcia River Forest

Jennifer Carah, Jason Pelletier

A two-page summary of salmon restoration efforts at the Garcia River Forest on the North Cost of California focusing on the reintroduction of wood in streams as a strategy.

2012 | Freshwater | Publications & Reports

Where Does California’s Water Come From? Land conservation and the watersheds that supply California’s drinking water

Kirk Klausmeyer, Katie Fitzgerald

Key to protecting drinking water for all Californians is understanding the sources and health of the thier watersheds. This study maps California's surface drinking water sources, the watersheds…

2012 | Freshwater | Maps & Webmaps

California's Flood Risk: Green Solutions for an Uncertain Future

Kirk Klausmeyer, Megan Webb

Almost 9 million acres of California are at risk from flooding. These flood zones cover 16% of the state’s urban and suburban development, and 36% of the state’s land dedicated to…

2012 | Freshwater | Terrestrial | Marine | Science | Video

Saving Salmon One Log at a Time

The Nature Conservancy, Jennifer Carah

Salmon and trout thrive in streams with cool water, low levels of sand and silt, and deep, shaded pools. Intensive forest management in California over the last 150 years led to the removal of these…