In a normal year, groundwater accounts for 40 percent of California’s water supply. That number jumps to 60 percent during a drought. It’s also critically important for sustaining certain types of aquatic, terrestrial and coastal ecosystems.

Yet decades of unregulated groundwater withdrawal has compromised that ability to provide for people and nature. Wells dry up, water quality declines, and rivers, wetlands, and springs disappear.

To address this problem, California passed legislation requiring that groundwater basins be managed sustainably. We still face gaps, however, in our understanding of how to manage these basins to ensure the health of the ecosystems they support. Conservancy scientists are working with water managers and state agencies to close those gaps.

Science in Action

Freshwater | Science

Groundwater Dependent Ecosystems

How can we manage groundwater to benefit both people and nature?

Freshwater | Technology | Science

Groundwater for Ecosystem Health

How much groundwater do ecosystems need to survive?

2024 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Maximizing the habitat value for shorebirds of private landowner incentive programs

Erin. E. Conlisk, Gregory H. Golet, Mark D. Reynolds, Nathan Elliot. and Matthew E. Reiter

Shorebirds are the second fastest declining group of birds in North America. To reverse this trend, The Nature Conservancy has been implementing BirdReturns, a habitat incentive program that pays…

2024 | Freshwater | Terrestrial | Science | Publications & Reports

Potential Impacts to Biodiversity from Proposed Lithium Extraction in Nevada and California

Michael J. Clifford, Sophie S. Parker, Laurel Saito, Brian S. Cohen, Naomi S. Fraga

Lithium batteries are important for the clean energy transition in the United States because they are used in electric vehicles and for grid power storage. However, lithium extraction may have impacts…

2024 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2023 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…

2024 | Freshwater | Terrestrial | Publications & Reports

Potential impacts of proposed lithium extraction on biodiversity and conservation in the contiguous United States

Sophie S. Parker, Michael J. Clifford, Brian S. Cohen

To address climate change, the United States is incentivizing the production of electric vehicles containing domestically derived lithium batteries. Extracting this lithium may have environmental…

2024 | Freshwater | Terrestrial | Publications & Reports

Expert bioblitz on the Atwood Preserve

Michael Clifford, Sophie Parker, Matt Rader, Lydia Bailey, Naomi Fraga, Chris Hass, Estella Hernandez, Jan Kempf, Lois Merkler, Michael Swink

The Amargosa River supports one of the most outstanding suites of endemic and imperiled species in the world. In 2019, TNC acquired the Atwood Preserve in the river’s headwaters, the…

2023 | Freshwater | Terrestrial | Science | Publications & Reports

Statistical evaluation of the similarity of characteristics in springs of the California Desert, United States

Adam H. Love, Andy Zdon, Naomi S. Fraga, Brian Cohen, Maura Palacios Mejia, Rachel Maxwell, Sophie Parker

This paper presents results from the Mojave Desert Springs research project. The authors present a comprehensive statistical analysis of similarities between California desert springs. An observed…

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…

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

Informing waterfowl conservation by determining what habitats are least resilient during times of drought

Erin E. Conlisk, Kristin B. Byrd, Elliot Matchett, Austin A. Lorenz, Michael Casazza, Gregory H. Golet, Mark D. Reynolds, Kristin A. Sesser, and Matthew E. Reiter

Landscape-scale wetland conservation requires understanding how wildlife responds to dynamic freshwater habitat availability. This study examined this for dabbling ducks by comparing habitat…

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 | 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 | 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 | 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…

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

Planting Stormwater Solutions: A methodology for siting nature-based solutions for pollution capture, habitat enhancement, and multiple health benefits

Kelsey Jessup, Sophie S. Parker, John M. Randall, Brian S. Cohen, Rowan Roderick-Jones, Shona Ganguly, Jill Sourial

This paper presents results from Planting Stormwater Solutions, part of TNC’s Urban Conservation work in Los Angeles. The authors develop a methodology to prioritize siting of vegetated…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Biological responses to stream nutrients: A Synthesis of Science From Experimental Forests and Ranges

Kristen Wilson, Dale W. Johnson, Douglas F. Ryan, ed.

Authored by TNC staff and colleague, Chapter 8 of this report synthesizes environmental monitoring and studies performed at Sagehen Experimental Forest that are relevant to water quality regulatory…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Cannabis farms in California rely on wells outside of regulated groundwater basins

Christopher Dillis, Van Butsic, Jennifer Carah, Samuel Zipper, Theodore Grantham

Water management practices for cannabis farming in California are not well understood. This study examined permit reporting data and found that the vast majority (>75%) of permitted cannabis farms…

2021 | Freshwater | Planning | Science | Publications & Reports

Mind the Gaps: The Case for Truly Comprehensive Sustainable Groundwater Management

Barton H. Thompson, Jr., Melissa M. Rohde, Jeanette K. Howard, Sandi Matsumoto

In 2014, California’s landmark Sustainable Groundwater Management Act (SGMA) promised comprehensive management of California’s groundwater. This report, Mind the Gaps: The Case for Truly…

2021 | Freshwater | Terrestrial | Planning | Technology | Science | Data

Natural Communities Commonly Associated with Groundwater Version 2.0 (NCCAG 2.0)

Kirk Klausmeyer, Jeanette Howard, Melissa Rohde, Charlotte Stanley

The first step to sustainably manage groundwater dependent ecosystems (GDEs) is to identify where they are. The Nature Conservancy developed a statewide spatial database that provides locations of…