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?

2019 | Freshwater | Science | Publications & Reports

Cannabis and residential groundwater pumping impacts on streamflow and ecosystems in Northern California

Samuel C. Zipper, Jennifer K. Carah, Christopher Dillis, Tom Gleeson, Ben Kerr, Melissa M. Rohde, Jeanette K. Howard, Julie K.H. Zimmerman

Using a newly developed tool for estimating streamflow depletion from groundwater pumping, this study examined the impacts of ongoing groundwater pumping on streamflow and aquatic ecosystems in the Navarro watershed in rural, coastal California. The study found that common uses of groundwater in the watershed,…


2019 | Freshwater | Science | Publications & Reports

A Transdisciplinary Approach to Characterize Hydrological Controls on Groundwater-Dependent Ecosystem Health

Melissa M. Rohde, Sara B. Sweet, Craig Ulrich, Jeanette Howard

Groundwater plays an essential role in supporting freshwater species, riparian habitats, and migratory birds. These ecological communities, commonly referred to as groundwater-dependent ecosystems (GDEs), can suffer undesirable impacts from unsustainable pumping practices. This study assessed whether ecosystem health varied with groundwater availability in riparian forests in California’s…


2019 | Freshwater | Terrestrial | Science | Publications & Reports

First known survey of cannabis production practices in California

Houston Wilson, Hekia Bodwitch, Jennifer Carah, Kent Daane, Christy Getz, Theodore E. Grantham, Van Butsic

Cannabis has been an industry in the shadows for many decades and little studied. In partnership with U.C. Berkeley and U.C. Cooperative Extension, the Conservancy staff developed the first cannabis growers survey on cultivation practices in California. The goal of the survey was to understand…


2019 | Freshwater | Economics | Publications & Reports

Economic Tools to Achieve Groundwater Sustainability for Nature: Two Experimental Case Studies from California

Sandi Matsumoto, Melissa M. Rohde, Sarah Heard

Groundwater is a critical water supply around the world and is increasingly under threat from pumping that exceeds natural replenishment. Successful implementation of California's Sustainable Groundwater Management Act (SGMA) depends local agencies working with stakeholders to develop plans and implement projects that reduce groundwater use,…


2019 | Freshwater | Science | Publications & Reports

Critical Species LookBook: A compendium of California's threatened and endangered species for sustainable groundwater management

Rohde MM, Seapy B, Rogers R, Castañeda X, editors

Plant and animal species can rely on groundwater directly or indirectly for water, nutrients, and stable temperatures. The Critical Species LookBook is a compendium of 84 state and federally listed species likely to rely on groundwater in California. This document provides groundwater-relevant information for each…


2019 | Freshwater | Science | Publications & Reports

Rapid and Accurate Estimates of Streamflow Depletion Caused by Groundwater Pumping Using Analytical Depletion Functions

Samuel C. Zipper, Tom Gleeson, Ben Kerr, Jeanette K. Howard, Melissa M. Rohde, Jennifer Carah, Julie Zimmerman

Reductions in streamflow from groundwater pumping can negatively impact water users and aquatic ecosystems but are challenging to estimate due to the time and expertise required to develop numerical models often used in water management. This paper develops a new approach – a combination of…


2019 | Freshwater | Technology | Science | Maps & Webmaps

GDE Pulse: Monitoring Groundwater Dependent Ecosystems with Satellites

Kirk Klausmeyer, Falk Schuetzenmeister, Nathaniel Rindlaub, Tanushree Biswas, Melissa M. Rohde, Jeanette Howard

94,333 unique ecosystems depend on groundwater in California. GDE Pulse lets you see how they have changed over the last 30 years.  Groundwater managers and environmental stakeholders often lack information about the health of critical groundwater dependent ecosystems (GDEs). To fill this information gap, we…


2019 | Freshwater | Economics | Publications & Reports

SGMA's First Groundwater Market: An Early Case Study from Fox Canyon

Sarah Heard, E.J. Remson, Matthew Fienup, Siobhan King

In 2014, California passed the Sustainable Groundwater Management Act (SGMA) which regulates groundwater at scale for the first time, requiring the state’s largest source of stored water to be managed for long-term resilience. SGMA delegates the responsibility of achieving sustainable groundwater management by 2040 to…


2019 | Freshwater | Terrestrial | Science | Publications & Reports

The dark side of facilitation: native shrubs facilitate exotic annuals more strongly than native annuals

Jacob E. Lucero, Taylor Noble, Stephanie Haas, Michael Westphal, H. Scott Butterfield, Christopher J. Lortie

Previous work at the Carrizo Plain by this team in 2018 showed that native shrubs facilitated endangered blunt-nosed leopard lizard populations, and should be considered part of plans for habitat restoration in the San Joaquin Valley. This paper shows that shrubs have a dark…


2019 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Habitat restoration opportunities, climatic niche contraction, and conservation biogeography in California's San Joaquin Desert

Joseph A. E. Stewart, H. Scott Butterfield, Jonathan Q. Richmond, David J. Germano, Michael F. Westphal, Erin N. Tennant, Barry Sinervo

Due to limited water resources, there is a global trend toward the retirement of farmland, especially in the San Joaquin Valley in California where the Sustainable Groundwater Management Act could necessitate the retirement of more than 500,000 acres. This paper helps identify where, across the…


2018 | Freshwater | Terrestrial | Planning | Economics | Science | Publications & Reports

Groundwater sustainability in the San Joaquin Valley: Multiple benefits if agricultural lands are retired and restored strategically

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…


2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Better late than never: a synthesis of strategic land retirement and restoration in California

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…


2018 | Freshwater | Economics | Publications & Reports

California’s First Farmer-Led Groundwater Market

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…


2018 | Freshwater | Science | Microsite

Groundwater Resource Hub

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…


2018 | Freshwater | Science | Publications & Reports

Mojave Desert Springs and Waterholes: Results of the 2015-16 Mojave Desert Spring Survey

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,…


2018 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Ecological Values of the Amargosa River in California

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…


2018 | Freshwater | Science | Publications & Reports

Groundwater Dependent Ecosystems under the Sustainable Groundwater Management Act: Guidance for Preparing Groundwater Sustainability Plans

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).…


2017 | Freshwater | Terrestrial | Planning | Publications & Reports

Identification of potentially suitable habitat for strategic land retirement and restoration in the San Joaquin Desert

H. Scott Butterfield, Rodd Kelsey, Abigail Hart, Tanushree Biswas, Mark Kramer, Dick Cameron, Laura Crane, Erica Brand

California's Sustainable Groundwater Management Act (SGMA) established a framework for sustainable, local groundwater management. SGMA requires groundwater-dependent regions to halt overdraft and bring basins into balanced levels of pumping and recharge. As a result, agricultural land retirement is on the rise in the San Joaquin Valley, California’s largest agricultural region and home to…


2017 | Freshwater | Terrestrial | Planning | Publications & Reports

Rethinking the Grid: Optimizing California’s Transmission System For Renewable Energy

Energy+Environmental Economics for The Nature Conservancy, Arne Olson, Doug Allen, Vivian Li, Emily Leslie

California leads the nation in the transition to a clean energy economy. However, current transmission planning processes limit development of new renewable resources. This report (slide deck), produced for the Conservancy by Energy+Environmental Economics, analyzes an alternative transmission planning framework (Energy-Only) using the San Joaquin Valley as…


2017 | Freshwater | Planning | Science | Publications & Reports

A Global Synthesis of Managing Groundwater Dependent Ecosystems Under Sustainable Groundwater Policy

Melissa M. Rohde, Ray Froend, Jeanette Howard

Groundwater is a vital water supply worldwide for people and nature. However, species and ecosystems that depend on groundwater for some or all of their water needs, known as groundwater dependent ecosystems (GDEs), are increasingly becoming threatened worldwide. This paper provides an overview of how…