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 number jumps to 60… >>

Surface Flows

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

Science in Action

Freshwater | Terrestrial | Technology | Economics | Science

Dynamic Conservation

In an era of rapid global change, how can conservationists provide habitat where and when nature needs it most?

Freshwater | Terrestrial | Science

Not Leaving it to Beaver

Can we restore meadows by mimicking beavers?

2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Water Supply and Habitat Resiliency for a Future Los Angeles River: Site-Specific Natural Enhancement Opportunities Informed by River Flow and Watershed-Wide Action

Brian Cohen, Shona Ganguly, Sophie Parker, John Randall, Jill Sourial, and Lara Weatherly of The Nature Conservancy, Land IQ, Natural History Museum Los Angeles County, WRC Consulting Services Inc., Travis Longcore, University of Southern California, Connective Issue, Inc.

As a basic principle of ecological systems, a watershed’s hydrology determines the flow characteristics of its river system. These flows define what the biological characteristics of that river will be, which in turn determine what kinds of habitat enhancement projects will succeed at various locations along…


2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Ecological spillover dynamics of organisms from urban to natural landscapes

Jill E. Spear, Erik K. Grijalva, Julia S. Michaels, Sophie S. Parker

This paper discusses the impact of urban-dwelling plants and animals on regional wildland populations, both within and across species. The authors reviewed the global conservation literature and identified seven ecological processes that have the potential to be affected by spillover from urban to wildland areas.…


2018 | Freshwater | Science | Microsite

Groundwater Resource Hub

Sandi Matsumoto, Gregg Werner, Melissa Rohde, Kirk Klausmeyer

Groundwater dependent ecosystems (GDEs) are plant and animal communities that require groundwater to meet some or all of their water needs. GDEs provide important benefits to California including habitat for animals, water supply, water purification, flood mitigation, erosion control, recreational opportunities and enjoyment of California’s…


2018 | Freshwater | Planning | Publications & Reports

A freshwater conservation blueprint for California: prioritizing watersheds for freshwater biodiversity

Jeanette K. Howard, Kurt A. Fesenmyer, Theodore E. Grantham, Joshua H. Viers, Peter R. Ode, Peter B. Moyle, Sarah J. Kupferburg, Joseph L. Furnish, Andrew Rehn, Joseph Slusark, Raphael D. Mazor, Nicholas R. Santos, Ryan A. Peek, Amber N. Wright

Freshwater ecosystems are in peril globally. Threats to freshwater biodiversity are numerous and include habitat degradation, pollution, overexploitation, dam construction, species invasion, and hydroclimatic change. With conservation resources often limited, prioritization tooks are needed by land and water managers. To fill this need, the authors…


2018 | Freshwater | Science | Publications & Reports

Mojave Desert Springs and Waterholes: Results of the 2015-16 Mojave Desert Spring Survey

Prepared by Andrew Zdon & Associates Inc. for Transition Habitat Conservancy, The Bureau of Land Management, and The Nature Conservancy

The Mojave Desert within California, which spans four counties, exists as one of the most important ecological regions in the southwestern United States. Both the groundwater and surface water in the region support isolated, unique and diverse ecosystems, while also supporting human needs through domestic,…


2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Ecological Values of the Amargosa River in California

Sophie S. Parker, Jim Moore, Leonard Warren

The 185 mile-long Amargosa River, one of only two rivers with perennial flow in the California portion of the Mojave Desert, is fed by an ancient groundwater aquifer. The river provides habitat for hundreds of organisms, including a unique suite of rare, endemic, and imperiled…


2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Harnessing cross-border resources to confront climate change

Aburto-Oropeza, O., M. Edwards, S. Butterfield, and 93 additional authors

The U.S. and Mexico face many shared ecological changes due to the increased frequency and severity of droughts and rising energy demands; trends that entail economic costs for both nations and major implications for human well-being. This paper synthesizes current knowledge about the most pressing issues…


2018 | Freshwater | Science | Publications & Reports

Groundwater Dependent Ecosystems under the Sustainable Groundwater Management Act: Guidance for Preparing Groundwater Sustainability Plans

Rohde, M.M., S. Matsumoto, J. Howard, S. Liu, L. Riege, E.J. Remson

California's Sustainable Groundwater Management Act (SGMA) of 2014 is landmark legislation that empowers local agencies, known as groundwater sustainability agencies, to sustainably manage groundwater resources for social, economic and environmental benefits. SGMA also includes specific requirements to identify and consider impacts to groundwater dependent ecosystems


2018 | Freshwater | Terrestrial | Science | Publications & Reports

Using ricelands to provide temporary shorebird habitat during migration

Gregory H. Golet, Candace Low, Simon Avery, Katie Andrews, Christopher J. McColl, Rheyna Laney, Mark D. Reynolds

Migratory birds face great challenges due to the climate change, conversion of historical stopover sites, and other factors. To help address these challenges, the Conservancy launched a dynamic conservation incentive program to create temporary wetland habitats in harvested and fallow rice fields for shorebirds…


2017 | Freshwater | Science | Publications & Reports

Patterns and magnitude of flow alteration in California, USA

Julie K H Zimmerman, Daren M. Carlisle, Jason T. May, Kirk R. Klausmeyer, Theodore E. Grantham, Larry R. Brown, Jeanette K. Howard

The importance of the natural flow regime to stream and river health has received growing attention in recent years. Understanding natural flows and patterns of flow alteration is an important first step in improving the management of California’s rivers and streams for human and ecosystem…


2017 | Freshwater | Science | Data

California Natural Flows Database

Julie K.H. Zimmerman, Daren M. Carlisle, Jason T. May, Kirk R. Klausmeyer, Theodore E. Grantham, Larry R. Brown, Jeanette K. Howard

The Nature Conservancy and the United Stated Geological Survey (USGS) partnered to generate estimates of natural flows (expected streamflow in the absence of human modification) in all the streams and rivers in California (1950-2015). For more details on the methods and results see  Patterns and…


2017 | Freshwater | Terrestrial | Planning | Publications & Reports

Identification of potentially suitable habitat for strategic land retirement and restoration in the San Joaquin Desert

H. Scott Butterfield, Rodd Kelsey, Abigail Hart, Tanushree Biswas, Mark Kramer, Dick Cameron, Laura Crane, Erica Brand

California's Sustainable Groundwater Management Act (SGMA) established a framework for sustainable, local groundwater management. SGMA requires groundwater-dependent regions to halt overdraft and bring basins into balanced levels of pumping and recharge. As a result, agricultural land retirement is on the rise in the San Joaquin Valley, California’s largest agricultural region and home to…


2017 | Freshwater | Terrestrial | Planning | Publications & Reports

Rethinking the Grid: Optimizing California’s Transmission System For Renewable Energy

Energy+Environmental Economics for The Nature Conservancy, Arne Olson, Doug Allen, Vivian Li, Emily Leslie

California leads the nation in the transition to a clean energy economy. However, current transmission planning processes limit development of new renewable resources. This report (slide deck), produced for the Conservancy by Energy+Environmental Economics, analyzes an alternative transmission planning framework (Energy-Only) using the San Joaquin Valley as…


2017 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2017 Annual Report

The Nature Conservancy deploys science to help overcome major challenges facing people and nature. In today’s fast-paced world, turning threats to nature into opportunities for conservation requires agility. The Conservation Science Catalyst Fund enables our science team to mobilize quickly — and produce the information…


2017 | Freshwater | Terrestrial | Marine | Technology | Economics | Science | Publications & Reports

Dynamic conservation for migratory species

Mark D. Reynolds, Brian L. Sullivan, Eric Hallstein, Sandra Matsumoto, Steve Kelling, Matthew Merrifield, Daniel Fink, Alison Johnston, Wesley M. Hochachka, Nicholas E. Bruns, Matthew E. Reiter, Sam Veloz, Catherine Hickey, Nathan Elliott, Leslie Martin, John W. Fitzpatrick, Paul Spraycar, Gregory H. Golet, Christopher McColl, Scott A. Morrison

What if instead of buying habitat, conservationists could rent it when and where nature needs it most? The Conservancy is using predictive models of shorebird movements, data from the citizen science program eBird, and NASA satellite wetland habitat data to create a habitat marketplace of…


2017 | Freshwater | Science | Publications & Reports

Managing diversions in unregulated streams using a modified percent-of-flow approach

Darren W. Mierau, William J. Trush, Gabriel J. Rossi, Jennifer K. Carah, Matthew O. Clifford, Jeanette K. Howard

The California water rights system often dis-incentivizes water management that benefits both nature and people by directing the timing of diversions to the summer when water is the most scarce. It makes more sense to divert water in the winter when it is plentiful, and…


2017 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Managing consequences of climate-driven species redistribution requires integration of ecology, conservation and social science

Timothy C. Bonebrake, Christopher J. Brown, Johann D. Bell, Julia L. Blanchard, Alienor Chauvenet, Curtis Champion, I-Ching Chen, Timothy D. Clark, Robert K. Colwell, Finn Danielsen, Anthony I. Dell, Jennifer M. Donelson, Birgitta Eveng°ard, Simon Ferrier, Stewart Frusher, Raquel A. Garcia, Roger B. Griffis, Alistair J. Hobday, Marta A. Jarzyna, Emma Lee, Jonathan Lenoir, Hlif Linnetved, Victoria Y. Martin, Phillipa C. McCormack, Jan McDonald, Eve McDonald-Madden, Nicola Mitchell, Tero Mustonen, John M. Pandolfi, Nathalie Pettorelli, Hugh Possingham, Peter Pulsifer, Mark Reynolds , Brett R. Scheffers, Cascade J. B. Sorte, Jan M. Strugnell, Mao-Ning Tuanmu, Samantha Twiname, Adriana Verg´es, Cecilia Villanueva, Erik Wapstra, Thomas Wernberg , Gretta T. Pecl

Climate change is driving the largest global redistribution of the planet’s species since the ice age. Species redistributions present challenges for human well-being, environmental management and sustainable development. Species redistribution also poses new questions for the study of ecosystems, conservation science and human societies that…


2017 | Freshwater | Planning | Science | Publications & Reports

A Global Synthesis of Managing Groundwater Dependent Ecosystems Under Sustainable Groundwater Policy

Melissa M. Rohde, Ray Froend, Jeanette Howard

Groundwater is a vital water supply worldwide for people and nature. However, species and ecosystems that depend on groundwater for some or all of their water needs, known as groundwater dependent ecosystems (GDEs), are increasingly becoming threatened worldwide. This paper provides an overview of how…