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.
In a normal year, groundwater accounts for 40 percent of California’s water supply. That number jumps to 60… >>
Californians have fundamentally altered many of the state’s rivers and streams with dams, pipes, and diversions, and the… >>
Randall, J.M., K. McEachern, J. Knapp, P. Power, S. Junak, K. Gill, D. Knapp, M. Guilliams
Chris Elphick, T. Rodd Kelsey, Catherine Hickey, Khara Strum, Paul Buttner, Monica Iglecia
Wetland birds, especially Sandhill Cranes, are heavily dependent on irrigated farmlands in the Central Valley of California after widespread conversion of natural habitats. TNC and its partners have had great success working with farmers to design and implement compatible management practices that make sure farms,…
Kristen Sesser, Monica Iglecia, Matthew Reiter, Khara Strum, Catherine Hickey, Rodd Kelsey, Daniel Skalos
Over 50% of waterbird habitat in the Central Valley of California is provided by flooded agricultural land. Each year non-breeding waterbird habitat decreases in the late winter as flooded agricultural fields are drained after waterfowl hunting season in late-January to prepare for the next crop.…
Rodd Kelsey, Abby Hart, H. Scott Butterfield, Dan Vink
Restoring habitat in retired farmland could reduce water demand and provide ecosystem services for farmers and local communities. In some areas of California, as a result of the Sustainable Groundwater Management Act (SGMA), it is likely that large amounts of agricultural land will need to…
Travis M. Hinkelman, Myfanwy Johnston, Joseph E. Merz, Julie Zimmerman
To restore degraded stream corridors and develop large-scale, sustainable watershed conservation strategies, it is essential for managers to consider—in order to ultimately re-establish—the habitat requirements of keystone species. For example, in order to restore salmon in the Central Valley of California, we need a clear…
Walter N. Heady, Brian S. Cohen, Mary G. Gleason, Joshua N. Morris, Sarah G. Newkirk, Kirk R. Klausmeyer, Hilary R. Walecka, Elizabeth Gagneron
Sea level rise presents a new challenge to coastal conservation. The authors quantified and mapped the vulnerability of habitats, imperiled species, and conservation lands to sea level rise throughout the entire California coast, where high biodiversity, high endemism, and 26.5 million people coincide. Combining habitat…
Chris Lortie, Alex Filazzola, Rodd Kelsey, Abigail Hart, Scott Butterfield
Over the past 100 years, California's Central Valley has undergone a massive transformation from desert to a mosaic of farmland and urban development. This transformation has also meant many desert species have lost habitat. Now, new groundwater regulations are calling for the retirement of more…
Annika T.H. Keeley, David D. Ackerly, Galli Basson, D. Richard Cameron, Lee Hannah, Nicole E. Heller, Patrick R. Huber, Patrick R. Roehrdanz, Carrie A. Schloss, James H. Thorne, Samuel Veloz, Adina M. Merenlender
Sarah Heard, E.J. Remson, Siobhan King, Sandi Matsumoto
The Conservancy has a vested interest in preserving farms in Ventura County because they buffer important river and wetland habitat from nearby urban lands. In western Ventura County, over 70% of groundwater use is agricultural. Due to requirements of the Sustainable Groundwater Management Act (SGMA), this use will…
Matthew E. Reiter, Nathan K. Elliott, Dennis Jongsomjit, Gregory H. Golet, Mark D. Reynolds
In the Central Valley of California, with 90% of the historic wetlands gone, waterbirds depend upon managed wetlands and seasonally flooded agriculture to meet their habitat needs. The 2013-2015 drought in the Central Valley was more severe than drought years during 2000-2011 and reduced waterbird…
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…
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.…
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…
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…
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,…
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…
Alexander C.A.D., F. Poulsen, D.C.E. Robinson, B.O. Ma , R.A. Luster
Management of the Sacramento River and Sacramento–San Joaquin Delta is one of California’s greatest challenges, requiring trade-offs between valued components that serve a multiplicity of conflicting purposes. This paper demonstrates an improved method for multiple-objective allocation of water based on a “turn-taking” optimization model. The…
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…
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 (GDEs).…
