Californians have fundamentally altered many of the state’s rivers and streams with dams, pipes, and diversions, and the State is home to some of the world’s most complex water delivery projects. As an unfortunate consequence, habitat for many freshwater species has been degraded or destroyed.

But, is it necessary to tradeoff the freshwater needs of birds, fish, and other species against the needs of farms and cities? Could freshwater flows be managed to better mimic the dynamics of their unimpaired past, dynamics to which native species have adapted and need to persist? And how should climate change considerations be incorporated into water management, to enhance the resilience of freshwater systems for both people and nature?

Our science is focused on tackling these questions.

Science in Action

Freshwater | Terrestrial | Science

Not Leaving it to Beaver

Can we restore meadows by mimicking beavers?

Freshwater | Terrestrial | Science

High Time for Conservation

How can science help us understand – and address – the environmental impacts of marijuana cultivation?

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 dis-incentivizes water management that benefits both nature and people. A strategy of diverting water when it is plentiful in the winter, and storing it for use in the summer, would mean more water security for people and more water in…


2017 | Freshwater | Terrestrial | Economics | Publications & Reports

Market-Based Mechanisms For Securing Environmental Water In California

Sarah Heard, Siobhan King, Eric Hallstein

California’s water supply is becoming increasingly unreliable. During dry times, consumptive use often outstrips supplies. As a result, people and nature suffer. This imbalance of supply and demand will likely grow worse if future demand for agricultural and urban water increases alongside a warming climate.…


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

Population and habitat objectives for avian conservation in California’s Central Valley riparian ecosystems

Kristen E. Dybala, Neil Clipperton, Thomas Gardali, Gregory H. Golet, Rodd Kelsey, Stefan Lorenzato, Ron Melcer, Jr., Nathaniel E. Seavy, Joseph G. Silveira

The Conservancy and partners are working to establish riparian ecosystems that provide sufficient habitat to support genetically robust, self-sustaining, and resilient bird populations in California's Central Valley. In this study, researchers selected 12 riparian landbird focal species as indicators of riparian ecosystem health and are…


2017 | Freshwater | Terrestrial | Planning | Publications & Reports

Informing watershed planning and policy in the Truckee River basin through stakeholder engagement, scenario development, and impact evaluation

Kristen Wilson, Erik Lowe, Stacey Wolny, Barry Nickel , Rodd Kelsey

This study demonstrates how science-based planning with stakeholder input can improve and direct conservation investments across existing state and jurisdictional boundaries. The authors set out to help direct the type, amount, and location of conservaiton investments in the Truckee River watershed in the Sierra Nevada…


2017 | Freshwater | Planning | Publications & Reports

Water for nature: What we can do today to help California’s rivers, streams and wetlands

Burns, C.E., A. Hoss, N. Smith, K. Klausmeyer, K. Fesenmeyer, A. Campbell, J. Carah, E. Forsburg, S. Heard, J.K. Howard, L. Hulette, S. Liu, P. Spraycar, B. Stranko, G. Werner, D. Wordham

This report identifies a set of strategies that will have the greatest impact on environmental flows, and to provide a resource for conservation organizations, resource agencies, and other stakeholders in California that may help create the conditions that allow freshwater species to thrive well into…


2016 | Freshwater | Science | Publications & Reports

Benefits and Economic Costs of Managed Aquifer Recharge in California

Debra Perrone, Melissa M. Rohde

Managed aquifer recharge (MAR) projects can play an important role in ensuring California manages its groundwater sustainably. This study, the first to investigate the benefits and economic costs of MAR projects in the state, found California MAR projects to be a cost-effective storage strategy, exhibit a…


2016 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

Pop-up wetland habitats benefit migrating birds and farmers

Christopher J. McColl , Katie Andrews, Mark Reynolds, Gregory H. Golet

In response to the decline of wetland habitats for migrating and wintering water birds in California, the Conservancy developed a program called BirdReturns that creates “pop-up” wetland habitat where and when birds need them most by enlisting farmers to flood their fields at specific times. This…


2016 | Freshwater | Science | Publications & Reports

Sustainable Groundwater Management: What We Can Learn from California's Central Valley Streams

The Nature Conservancy, RMC Consultants, Inc.

Groundwater is intimately connected to surface water, which has profound implications for sustainable water resource management. California has historically overlooked this important interaction and as a consequence, decisions about groundwater extractions have generally failed to address the resulting impacts to aquatic ecosystems such as rivers,…


2015 | Freshwater | Terrestrial | Publications & Reports

The benefits of crops and field management practices to wintering waterbirds in the Sacramento-San Joaquin River Delta of California

W. David Shuford , Matthew E. Reiter, Khara M. Strum, Michelle M. Gilbert , Catherine M. Hickey, Greg Golet

Although agricultural intensification is one of the largest contributors to the loss of global biodiversity, agricultural landscapes can provide valuable habitat for birds. Recognizing this, wildlife professionals are working to promote “wildlife-friendly” farming. In this paper, authors assessed the value to wintering waterbirds of different…


2015 | Freshwater | Planning | Maps & Webmaps

California’s Freshwater Conservation Blueprint map

Megan Webb, Kirk Klausmeyer, Jeanette Howard

The transformation of California into one of the most productive agricultural and urban landscapes in the world and a growing population have put unprecedented pressure on freshwater habitats, reducing them to a small fraction of their historic extent. Across the state, freshwater-dependent ecosystems have been…


2015 | Freshwater | Science | Publications & Reports

California Freshwater Blueprint: Phase I Overview

Jeanette K. Howard, Kirk R. Klausmeyer, Kurt A. Fesenmyer

California is one of the most productive agricultural and urban landscapes in the world with a growing population. These pressures have reduced aquatic and wetland habitats to a small fraction of their historic extent. Ecosystems dependent on freshwater have been degraded across the state, with…


2015 | Freshwater | Terrestrial | Technology | Publications & Reports

Abundance models improve spatial and temporal prioritization of conservation resources

Johnston, A., D. Fink, M. D. Reynolds, W. M. Hochachka, B. L. Sullivan, N. E. Bruns, E. Hallstein, M. S. Merrifield, S. Matsumoto, S. Kelling

Global declines in migratory species in response to accelerating habitat destruction and climate change challenge the scope and scale of conservation efforts. The ability to pinpoint where and when conservation interventions will have the greatest positive population impact is especially important for conservation of migratory…


2015 | Freshwater | Marine | Publications & Reports

Aligning Natural Resource Conservation and Flood Hazard Mitigation in California

Juliano Calil, Michael W. Beck, Mary Gleason, Matthew Merrifield, Kirk Klausmeyer, Sarah Newkirk

The U.S. National Flood Insurance Program has paid out more than $38 billion in claims since its inception in 1968, more than a third of which has gone to the 1% of policies that experienced multiple, repetitive losses. During the same period, the loss of…


2015 | Freshwater | Planning | Data

California Freshwater Species Database v2

Jeanette Howard, Kirk Klausmeyer, Kurt Fesenmyer

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. It provides a single source for geodata covering the plants and animals that rely on California’s freshwater resources to survive.…


2015 | Freshwater | Planning | Science | Publications & Reports

Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California

Jeanette K. Howard, Kirk R. Klausmeyer, Kurt A. Fesenmyer, Joseph Furnish, Thomas Gardali, Ted Grantham, Jacob V. E. Katz, Sarah Kupferberg, Patrick McIntyre, Peter B. Moyle, Peter R. Ode, Ryan Peek, Rebecca M. Quiñones, Andrew C. Rehn, Nick Santos, Steve Schoenig, Larry Serpa, Jackson D. Shedd, Joe Slusark, Joshua H. Viers, Amber Wright, Scott A. Morrison

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. It provides a single source for geodata covering the plants and animals that rely on California’s freshwater resources to…


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 using the federal Coastal and Marine Ecological Classification Standard (CMECS). A spatial database of…