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?

2022 | Freshwater | Terrestrial | Technology | Economics | Science | Publications & Reports

Developing an adaptive management approach to cowbird control on the Santa Clara River, California

Sophie S. Parker, Linnea S. Hall, Mary J. Whitfield, Laura Riege, Kathryn R. Selm, René Corado

This paper presents results from a field-based study that can be used to benefit songbirds in riverside habitats like those found along the Santa Clara River in Ventura County, California. Songbirds…

2022 | Freshwater | Terrestrial | Marine | Economics | Science | Publications & Reports

Unlocking FEMA’s Hazard Mitigation Funding for Coral Reef Restoration: A Feasibility Study in Maui, Hawaii

UC Santa Cruz (Austen E. Stovall, Michael W. Beck), The Nature Conservancy (Alyssa Mann, Tamaki Bieri), Radbridge/formerly Earth Economics (Johnny Mojica, Rowan Schmidt)

Climate change poses severe threats to coastal communities and the ecosystems on which they depend. Warming ocean temperatures increase the magnitude and frequency of storm and coral bleaching events,…

2022 | Freshwater | Science | Publications & Reports

Water Resources Allocation and Agriculture: Allocations and Environmental Flows

Eric D. Stein, Michael E. McClain, Ashmita Sengupta, Theodore E. Grantham, Julie K.H. Zimmerman, Sarah M. Yarnell

In this chapter of Water Resources Allocation and Agriculture, the authors provide insights on how to integrate environmental flows into water allocation for agriculture across the world. They argue…

2022 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Stress Testing the BCA Toolkit with Nature-based Solutions: Observations and Recommendations for FEMA

The Nature Conservancy, Earth Economics

FEMA requires that hazard mitigation projects must be cost-effective to the federal government, as demonstrated in a Benefit-Cost Analysis (BCA), which compares the present value of a project’s…

2022 | Freshwater | Terrestrial | Science | Publications & Reports

Potential Lithium Extraction in the United States: Environmental, Economic, and Policy Implications

Sophie S. Parker, Bradley Franklin, Brian S. Cohen, Melissa M. Rohde, Michael Clifford, Andrew Williams

Climate change will cause severe financial, social, and environmental upheaval if a massive reduction in carbon emissions is not achieved by 2030. To address this challenge, rechargeable lithium-ion…

2022 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Informing shorebird conservation by determining when and how much habitat is needed in wet and dry years

Gregory. H. Golet, Kristen. E. Dybala, Matthew. E. Reiter, Kristin. A. Sesser, Mark Reynolds, Rodd Kelsey

Shorebirds have declined precipitously in North America in the last 50 years, primarily due to the loss of wetlands. Incentive programs that pay farmers to create temporary wetland habitat on idled…

2022 | Freshwater | Terrestrial | Marine | Planning | Technology | Science | Publications & Reports

Prioritizing actions: spatial action maps for conservation

Heather Tallis, Joe Fargione, Edward Game, Rob McDonald, Leandro Baumgarten, Nirmal Bhagabati, Rane Cortez, Bronson Griscom, Jonathan Higgins, Christina M. Kennedy, Joe Kiesecker, Timm Kroeger, Trina Leberer, Jennifer McGowan, Lisa Mandle, Yuta J. Masuda, Scott Morrison, Sally Palmer, Rebecca Shirer, Priya Shyamsundar, Nicholas H.Wolff, and Hugh P. Possingham

Spatial analysis is a powerful tool in conservation planning. Yet it is often under-deployed as a means of elucidating which conservation actions may deliver the highest return on investment. This…

2022 | Freshwater | Terrestrial | Publications & Reports

Restoration richness tipping point meta-analysis: finding the sweet spot

Christopher J. Lortie, Maria Florencia Miguel, Alessandro Filazzola, Harry Scott Butterfield

Climate change, drought, and water scarcity are driving major land transformations in dryland ecosystems globally. Historically these ecosystems have been disproportionately degraded due to widespread…

2022 | Freshwater | Terrestrial | Marine | Planning | Technology | Science | Maps & Webmaps

The Mitigation Wizard

Carrie Schloss, Liz O’Donoghue, Dan Rademacher, Patric Huber, Jodi McGraw, Kim Becerril, Janine Knapp

Every year, infrastructure agencies and developers spend hundreds of millions of dollars to mitigate for impacts to sensitive species and habitats. These mitigation sites are often piecemeal projects,…

2022 | Freshwater | Planning | Science | Publications & Reports

A Machine Learning Approach to Predict Groundwater Levels in California Reveals Ecosystems at Risk

Melissa M. Rohde, Tanushree Biswas, Ian W. Housman, Leah S. Campbell, Kirk R. Klausmeyer, Jeanette Howard

Groundwater dependent ecosystems (GDEs) are increasingly threatened worldwide, but the shallow groundwater resources that they are reliant upon are seldom monitored. In this study, the researchers…

2022 | Freshwater | Planning | Science | Maps & Webmaps

SAGE: Shallow Groundwater Estimation Tool

Melissa M. Rohde, Tanushree Biswas, Ian W. Housman, Leah S. Campbell, Kirk R. Klausmeyer, Jeanette Howard

Groundwater dependent ecosystems (GDEs) are critical habitats throughout California that rely on shallow groundwater. Unfortunately, only a small subset of wells provide monitoring data for shallow…

2022 | Freshwater | Terrestrial | Marine | Planning | Publications & Reports

The Guidebook for FEMA Hazard Mitigation Grants: Promoting Nature-Based Mitigation Through FEMA Mitigation Grants

The Nature Conservancy, AECOM

With increase in devasting storms and wildfires due to climate change, we need solutions to help mitigate the impact. Traditionally, “gray” or “hard” infrastructure…

2022 | Freshwater | Planning | Science | Publications & Reports

Groundwater dependence of riparian woodlands and the disrupting effect of anthropogenically altered streamflow

Melissa M. Rohde, John C. Stella, Dar A. Roberts, Michael Bliss Singer

This study combines satellite, groundwater, and streamflow data over a 5 year period (2015-2020) to understand the impacts of groundwater depth and streamflow alteration on groundwater-dependent…

2022 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

Quantity and fate of synthetic microfiber emissions from apparel washing in California and strategies for their reduction

Roland Geyer, Jenna Gavigan, Alexis M. Jackson, Vienna R. Saccomanno, Sangwon Suh, Mary G. Gleason

Synthetic microfibers are the most prevalent type of microplastic and apparel washing is a major source of microfiber pollution. Using California as a case study to estimate the magnitude of…

2022 | Freshwater | Science | Publications & Reports

Hydraulic Properties of the Riffle Crest and Applications for Stream Ecosystem Management

Gabriel Rossi, Darren Mierau, Jennifer Carah

A simple stream depth measurement at the deepest part of a riffle crest in a river or stream provides an easy-to-measure and inexpensive metric for ecological researech, environmental flow management,…

2022 | Freshwater | Technology | Science | Publications & Reports

Modeling Functional Flows in California’s Rivers

Theodore E. Grantham, Daren M. Carlisle, Jeanette Howard, Belize Lane, Robert Lusardi, Alyssa Obester, Samuel Sandoval-Solis, Bronwen Stanford, Eric D. Stein, Kristine T. Taniguchi-Quan, Sarah M. Yarnell, Julie K. H. Zimmerman

Protecting water in rivers is made more challenging by the lack of quantitative estimates of the amount of water required to protect river ecosystems. The authors developed a model and made…

2022 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Transforming Palmyra Atoll to native-tree dominance will increase net carbon storage and reduce dissolved organic carbon reef runoff

Kate Longley-Wood, Mary Engels , Kevin D. Lafferty, John P. McLaughlin, Alex Wegmann

Native forests on tropical islands have been displaced by non-native species, leading to calls for their transformation. Simultaneously, there is increasing recognition that tropical forests can help…

2022 | Freshwater | Science | Publications & Reports

Functional Flows in Groundwater-Influenced Streams: Application of the California Environmental Flows Framework to Determine Ecological Flow Needs

Sarah M. Yarnell, Ann Willis, Alyssa Obester, Ryan A. Peek, Robert A. Lusardi, Julie Zimmerman, Theodore E. Grantham, Eric D. Stein

Very few rivers have protections to protect flow for species and ecosystems, in part because of the complexity and resources required to develop ecological flow criteria - the amount of water needed…

2022 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2021 Annual Report

Brynn Pewtherer, Scott Morrison

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…

2021 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Using information on forest succession to advance strategies for salmon recovery and carbon storage in meandering river systems

John C. Stella, Li Kui, Gregory H. Golet, Frank Poulsen

Streamside forests are incredibly important for fish, birds and other wildlife. They are also valuable for storing carbon which is needed to combat climate change. This is especially the case in…