About

Debra Perrone is an Associate Professor of UCSB’s Environmental Studies Program. She received her PhD in Environmental Engineering at Vanderbilt University in 2014, where she was awarded first honors as the Graduate School’s Founder’s Medalist. Prior to joining UCSB, she was a postdoctoral research scholar at Stanford University with a dual appointment in the Department of Civil and Environmental Engineering and the Woods Institute for the Environment. Her research integrates methods from engineering, physical science, and law to inform water sustainability and policy, focusing on water scarcity challenges and tradeoffs facing society. She has been awarded fellowships from the Environmental Protection Agency and National Science Foundation for her work. Debra is also a co-author of a textbook on global water resources, emphasizing water science and policy.

Research topics

• Environmental science
• Geology
• Ecology
• Water resource management
• Economics
• Biology
• Business
• Natural resource economics
• Environmental resource management
• Geomorphology
• Environmental planning
• Oceanography
• Geography

Selected publications

• Groundwater sustainability, drinking water, and environmental justice in California’s Central Valley, USA

  Hydrogeology Journal · 2026-04-29

  articleOpen access

  Abstract Groundwater is a critical drinking water source globally. However, drinking water wells, particularly domestic wells, tend to be shallower than those used for agricultural purposes, which makes them vulnerable to drying if groundwater levels decline. This creates tensions in the administration of laws that aim to protect access to groundwater for vulnerable communities. Some laws consider impacts on such communities through references to disadvantaged communities or environmental justice, which facilitate special consideration of the potentially unfair treatment of certain populations. This research examines the adequacy of groundwater-related laws for responding to environmental justice concerns in the Kings Subbasin of the Central Valley, a low-income, groundwater-dependent, and environmental risk-burdened region in California, USA. It examines both laws on paper and their implementation in practice. A fragmented system of laws emerges, with weaknesses in addressing risks of groundwater depletion, relative to quality concerns; diverging definitions of the vulnerable communities that deserve special attention; and further differences in how a single law is implemented in practice by different agencies. Local regulatory agencies charged with addressing depletion do not protect, nor try to protect, drinking water wells from running dry, which poses justice risks for communities facing threats to their drinking water. Avenues for strengthening support for considering environmental justice in groundwater laws include clearer references to environmental justice in laws that focus on sustainable aquifer levels, and clarifying the populations of concern at the heart of these provisions, supported by a reasoned approach to determining the relevant characteristics of vulnerability.

  PublisherDOI

• Undrainable pore spaces comprise half of US groundwater storage

  2025-08-28

  preprintOpen access

  Groundwater is vital to global freshwater access, streamflow generation, and biogeochemical cycling, but not all groundwater can be drained due to adhesive and capillary forces. Quantifying the proportion of groundwater that can be drained—and is, thus, theoretically recoverable—is critical for characterising groundwater’s role in earth system processes. Unfortunately, estimates of theoretically recoverable groundwater are poorly constrained due to a lack of three-dimensional lithologic observations. Here we analyse ~19.2 million 3D lithologic observations recorded in ~3.7 million drilling reports across the United States. We show that only half of US groundwater is theoretically recoverable by wells due to the abundance of aquitards, which retain most of their water when drained. The abundance of aquitards emphasizes that the great majority of groundwater is stored in confined aquifers, which are often more sensitive to rapid groundwater-level declines than shallower unconfined aquifers. The widespread prevalence of aquitards and confined conditions suggests that even modest groundwater pumping can lead to substantial drawdown in many aquifers, inducing land subsidence and creating potential water quality risks.

  PublisherOA PDFDOI

• Accelerated Decline of Groundwater Levels in the 21st century, globally

  2024-03-08

  preprintOpen access

  Groundwater is a vital resource for direct consumption as well as for agriculture, particularly in arid and semiarid climates where groundwater is often a primary water source for irrigation. Here, we analyze more than 170,000 groundwater level timeseries across the globe. We show that groundwater level declines accelerated over the past four decades. Accelerated declines are especially widespread in dry regions with extensive cropland. However, our study also reveals that there are areas where interventions have led to groundwater levels to recover.  This result provides a ray of hope for sustainable management of vital groundwater resources in the decades to come.

  PublisherDOI

• Humans are depleting groundwater worldwide, but there are ways to replenish it

  2024-01-24

  article
  PublisherDOI

• Rapid groundwater decline and some cases of recovery in aquifers globally

  Nature · 2024 · 533 citations

  • Environmental science
  • Water resource management
  • Geology

  ) are widespread in the twenty-first century, especially in dry regions with extensive croplands. Critically, we also show that groundwater-level declines have accelerated over the past four decades in 30% of the world's regional aquifers. This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.

  PublisherOA PDFDOI

• ENVIRONMENTAL RISKS AND OPPORTUNITIES OF ORPHANED OIL AND GAS WELLS IN THE UNITED STATES

  Abstracts with programs - Geological Society of America · 2023-01-01 · 2 citations

  article
  PublisherDOI

• Environmental risks and opportunities of orphaned oil and gas wells in the United States

  Environmental Research Letters · 2023-06-20 · 48 citations

  articleOpen access

  Abstract Hundreds of thousands of documented and undocumented orphaned oil and gas wells exist in the United States (U.S.). These wells have the potential to contaminate water supplies, degrade ecosystems, and emit methane and other air pollutants. Thus, orphaned wells present risks to climate stability and to environmental and human health, which can be reduced by plugging. To quantify environmental risks and opportunities of well plugging at the national level, we analyze data on 81 857 documented orphaned wells across the U.S. We find that <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>&gt;</mml:mo> </mml:math> 4.6 million people live within 1 km of a documented orphaned well. 35% of the documented orphaned wells are located within 1 km of a domestic groundwater well, yet only 8% of the wells have groundwater quality data within a 1 km radius. Methane emissions from the documented orphaned wells represent approximately 3%–6% of total U.S. methane emissions from abandoned oil and gas wells, but this estimate is based on measurements at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>&lt;</mml:mo> </mml:math> 0.03% of U.S. abandoned wells. 91% of the documented orphaned wells overlie formations favorable for geologic storage of carbon dioxide and hydrogen, meaning that orphaned well plugging can reduce leakage risks from future storage projects. Finally, we estimate plugging costs for documented orphaned wells to exceed the $4.7 billion federal funding by 30%–80%, emphasizing the importance of prioritizing federal spending on wells with large remediation benefits. Overall, environmental monitoring data are not extensive enough to quantify risks, especially those related to air and water quality and human health. Plugging orphaned wells can provide opportunities for geologic storage of carbon dioxide and hydrogen and geothermal energy development, thereby facilitating efforts to transition to net-zero energy systems. Our analysis on environmental risks and opportunities of orphaned wells provides a framework that can be used to manage the millions of documented and undocumented orphaned wells in the U.S. and abroad.

  PublisherOA PDFDOI

• Stakeholder integration predicts better outcomes from groundwater sustainability policy

  Nature Communications · 2023-06-27 · 55 citations

  articleOpen access1st authorCorresponding

  Natural resources policies that promote sustainable management are critical for protecting diverse stakeholders against depletion. Although integrating diverse stakeholders into these policies has been theorized to improve protection, empirical evidence is lacking. Here, we evaluate 108 Sustainability Plans under California's Sustainable Groundwater Management Act to quantify how well stakeholders are integrated into plans and protected from groundwater depletion. We find that the majority of Sustainability Plans do not integrate or protect the majority of their stakeholders. Nevertheless, our results show that when stakeholders are more integrated into a Sustainability Plan, they are more likely to be protected, particularly for those that lack formal access to decision-making processes. Our findings provide strong empirical evidence that integrating diverse stakeholders into sustainability planning is beneficial for stakeholders who are vulnerable to the impacts of natural resource depletion.

  PublisherOA PDFDOI

• Recycled water could recharge aquifers in the Central Valley

  California Agriculture · 2023-07-05 · 2 citations

  articleOpen access

  Drawing out too much groundwater, or overdrafting, is a serious problem in California. As a result, groundwater sustainability agencies are considering using recycled municipal wastewater to recharge aquifers. In our study, we employ suitability mapping and the models C2VSimFG and Ichnos to identify appropriate areas for managing aquifer recharge with recycled water in California's Central Valley. The factors that influence suitability include soil properties, proximity to recycled water sources, and the residence time, or amount of time that recharged water spends underground. There are many suitable areas in the Central Valley that are immediately adjacent to water recycling facilities. However, adequate supply is an issue in most locations. Roughly half of the groundwater sustainability agencies in critically overdrafted basins of the Central Valley have enough potentially suitable locations to meet their recharge goals, but not all of them have access to enough recycled water. The methods demonstrated here can serve as tools for agencies considering using recycled water for aquifer recharge.

  PublisherOA PDFDOI

• Global Economic Limits of Groundwater When Used as a Last Resort for Irrigation

  Research Square · 2022-07-29 · 7 citations

  preprintOpen access
  PublisherOA PDFDOI

Recent grants

• NSF East Asia and Pacific Summer Institute (EAPSI) for FY 2013 in Singapore

  NSF · $70 · 2013–2014

Frequent coauthors

• Scott Jasechko

  University of California, Santa Barbara

  30 shared

• George M. Hornberger

  Vanderbilt University

  24 shared

• Leslie L. Duncan

  9 shared

• James W. Kirchner

  University of California, Berkeley

  9 shared

• J. H. Jacobi

  9 shared

• Rebecca Nelson

  University of Melbourne

  8 shared

• Ying Fan

  Rutgers, The State University of New Jersey

  6 shared

• Tom Gleeson

  University of Victoria

  6 shared

Education

• PhD, Civil and Environmental Engineering

  Vanderbilt University

  2014

Awards & honors

• First Honors as the Graduate School’s Founder’s Medalist