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 | 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?

2023 | Freshwater | Microsite

Drought Flows Monitor

Julie Zimmerman, Jennifer Carah, Kirk Klausmeyer, Gabe Rossi, Mia Van Docto, Jeanette Howard, Charlie Schneider, Matt Clifford, Monty Schmitt

Drought conditions are occurring with more frequency, greater severity, and longer duration under climate change. Human water use compounds the effects of drought, further stressing California’s ecosystems, impacting farms, rural communities and urban water supplies. The Salmon and Steelhead Coalition developed a Drought Flows Monitor…


2023 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Expanding the Role of Nature-based Solutions in FEMA’s Hazard Mitigation Assistance Programs: Lessons and Recommendations

The Nature Conservancy, radbridge, Earth Economics

FEMA increasingly recognizes and emphasizes the role of nature-based solutions (NBS) for building community resilience to hazards like flood, wildfire, and drought, and the agency has made remarkable progress on policies and resources to support NBS in a relatively short period. However, anecdotally it remains…


2023 | Freshwater | Terrestrial | Marine | Planning | Economics | Publications & Reports

Valuing the Flood Reduction Benefits of Marsh Restoration

Taylor-Burns, R., Heard, S., Beck, M. W.

There is growing evidence for the beneficial role that wetlands can play in reducing flood risk, but in many urban estuaries, coastal development has resulted in dramatic habitat loss and fragmentation. In the past several decades, marsh restoration has emerged as a core management objective…


2023 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2022 Annual Report

Scott Morrison, Brynn Pewtherer

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…


2023 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

Floristic patterns and conservation values of Mojave and Sonoran desert springs in California

Naomi S. Fraga, Brian S. Cohen, Andy Zdon, Maura Palacios Mejia, Sophie S. Parker

This paper presents novel botanical inventories of 48 desert springs as part of the Mojave Springs Research Project. The authors assess plant species composition and richness within and between springs and evaluate how botanical diversity relates to physical and hydrological parameters. The results of…


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

Environmental & Historic Preservation Primer for Nature-Based Hazard Mitigation

The Nature Conservancy, FEMA, Nonlinear Ventures, radbridge, Earth Economics

To address the increasing risk of catastrophic flooding, wildfire and other climate-related threats, communities are pursuing nature-based solutions (NBS) and seeking FEMA hazard mitigation funds to support this work. Of all the required activities, the Environmental & Historic Preservation (EHP) review is often cited as…


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 such as the Least Bell’s Vireo suffer population declines in part because Brown-headed…


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, allowing less time for recovery amidst these threats. Coral reefs complex and stable structure protects against…


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 future benefits and costs. A BCA is required for the vast majority of FEMA-funded hazard mitigation projects,…


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 batteries will play a key role in transitioning the energy and transportation sectors away from fossil fuel…


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 paper presents a framework for “spatial action mapping” and discusses how it can improve conservation…


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 agricultural conversion. Because of these pressures, there are significant opportunities for rewilding and restoration of these dryland ecosystems. This global…


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, which can result in islands of mitigation. Regional advance mitigation programs seek to change this paradigm so…


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 used satellite-based remote sensing, climate data, and machine learning to predict groundwater levels over a 35 year period (1985…


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 groundwater. This tool, developed for a publication in Frontiers in Earth Science, uses satellite data and machine learning tools to…


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 solutions that rely on engineering projects using concrete and steel have dominated efforts to manage risk and mitigate hazard impacts…


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 vegetation across California. The study shows that deeper groundwater levels resulted in poor vegetation health, but that current water management…


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 microfiber emissions and evaluate mitigation approaches, the authors estimate that in 2019 over 4,850,000 pounds (2.2…


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, and habitat assessment. This paper describes measurement methods, as well as ways to use riffle measurements…


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 sequester carbon that would otherwise enter the atmosphere. At Palmyra Atoll, efforts are underway to transform the rainforest…