About

Scott Jasechko is a Professor of water resources at the University of California, Santa Barbara's Bren School of Environmental Science & Management. His research utilizes large datasets to understand how to preserve the quality and sustain the quantity of river water and groundwater resources around the globe. Before joining UCSB in November 2017, Scott completed his doctorate at The University of New Mexico and was on the faculty at the University of Calgary for three years. His work has been recognized with numerous early career awards, including the Kohout Early Career Award from the Geological Society of America in 2018, the Hydrologic Sciences Early Career Award from the American Geophysical Union in 2021, a CAREER Award from the National Science Foundation in 2021, and the Macelwane Medal from the American Geophysical Union in 2022.

Research topics

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

Selected publications

• Link between residence times and groundwater renewability obscured by hydraulics

  New Trends in Mathematical Science · 2026-01-01

  article

  Aquifer residence times are commonly used to make inferences about groundwater system behaviour. However, the link between average aquifer residence times and hydraulic response times which control groundwater storage changes relevant to sustainable pumping, remains unclear. Here, we show that water levels in some aquifers containing fossil groundwater are controlled by modern climates while many others are affected by past climates over periods shorter than their aquifer residence times.

• Global cases of groundwater recovery after interventions

  Science · 2026-03-19 · 1 citations

  article1st authorCorresponding

  Groundwater depletion poses a challenge to irrigated agriculture and water access. Depleted aquifers can be refilled, but the interventions that have successfully refilled depleted aquifers are rarely reviewed. This work reviews 67 cases of groundwater recovery, where groundwater levels rose after a prolonged period of decline. The interventions that spurred groundwater recovery included policy changes, artificial groundwater recharge, and increased reliance on another water source instead of groundwater. Groundwater recovery can improve water access, restore ecosystems, slow seawater intrusion, and halt land subsidence. However, excessive groundwater recovery can waterlog soils, destabilize buildings, increase liquefaction risks, and intensify flood hazards. This Analytical Review describes how groundwater depletion trends have been reversed through interventions. Stakeholders and managers may consider adapting aspects of these interventions to address groundwater depletion elsewhere.

  PublisherDOI

• Renewability of fossil groundwaters affected by present-day climate conditions

  Nature Geoscience · 2026-02-05

  articleOpen access
  PublisherOA PDFDOI

• A Brazilian groundwater dataset for advancing integrated water surface and groundwater management 

  2025-03-14

  preprintOpen access

  Groundwater plays a crucial role in meeting both human and ecosystem water needs. Its importance is expected to grow due to increasing water demand and the impacts of climate change on surface water resources, particularly in the Southern Hemisphere, where irrigated agricultural expansion continues to intensify. However, limitations in the spatio-temporal coverage of groundwater monitoring networks constrain our understanding of surface–groundwater interaction dynamics. Here, we present a groundwater well dataset for Brazil. It encompasses compiled and standardized well data from Geological Survey of Brazil projects. The harmonized dataset, which was validated by the Geological Survey of Brazil, underwent rigorous quality assurance and quality control procedures to ensure accuracy, adhering to principles of transparency and data integrity. The dataset includes over 351,000 wells spanning from the early 1900s to 2024, including 472 monitoring wells with daily water level measurements from 2010 to 2024. In addition to information on well location, primary use, and static water level, the dataset includes variables that can support integrated surface and groundwater management, such as distance to the nearest river, land use, and aquifer data. The potential applications of this dataset are wide-ranging. Here, we demonstrate two applications that can be replicated with other groundwater datasets. First, we compared well water levels with nearby river water levels to identify the direction of flow between Brazilian rivers and aquifers. The results indicated that over 55% of the analyzed wells in unconfined aquifers have water levels below those of the nearest river, suggesting that river water may seep into the underlying aquifer. Second, we applied the analytical depletion functions developed by Glover and Balmer to wells in unconfined aquifers to estimate streamflow depletion caused by groundwater pumping. The results suggested that approximately 9% of the analyzed rivers experience a streamflow depletion fraction exceeding 10% of their baseflow. These findings have the potential to enhance the integrated management of surface and groundwater resources in Brazil. Ultimately, we hope this accessible dataset fosters collaboration across the fields of groundwater hydrology, surface water hydrology, and water management.

  PublisherDOI

• Undrainable pore spaces comprise half of US groundwater storage

  2025-08-28

  preprintOpen accessSenior author

  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

• Climate sensitivity of groundwater recharge

  2025-03-14

  preprintOpen access

  Groundwater recharge is fundamental to supporting sustainable groundwater use for both ecosystems and human water withdrawals. Rates of recharge, and how these rates are affected by climate change, remain poorly constrained due to uncertain models and limited recharge measurements. We develop an emerging relationship between measurements of recharge and climatic aridity. This relationship suggests that recharge tends to be most sensitive to climatic changes in regions where potential evapotranspiration slightly exceeds precipitation. In these regions, even modest aridification can significantly reduce groundwater recharge. Future climate-driven changes in recharge are likely to be primarily influenced by shifts in precipitation, with groundwater recharge typically responding more strongly than the precipitation changes themselves. Measurements of recharge are more sensitive to variations in aridity than recharge simulated by several global hydrological models is. As a result, the impacts of climate change on groundwater replenishment and the sustainability of groundwater use for humans and ecosystems are likely greater than previously estimated.

  PublisherDOI

• Majority of global river flow sustained by groundwater

  Nature Geoscience · 2024-07-19 · 118 citations

  articleOpen access
  PublisherOA PDFDOI

• Widespread potential for streamflow leakage across Brazil

  Nature Communications · 2024-11-25 · 19 citations

  articleOpen access

  River-aquifer interactions play a crucial role in water availability, influencing environmental flows and impacting climate dynamics. Where groundwater tables lie below river water levels, stream water can infiltrate into the underlying aquifer, reducing streamflow. However, the prevalence of these "losing" rivers remains poorly understood due to limited national-wide in situ observations. Here we analyze water levels in 17,972 wells across Brazil to show that most of them (55%) lie below nearby stream surfaces, implying that these nearby streams are likely seeping into the subsurface. Our results demonstrate the widespread potential for stream water losses into underlying aquifers in many regions of the country, especially in areas with extensive groundwater pumping. Our direct observations underscore the importance of conjunctively managing groundwater and surface water, and highlight the widespread risk of streamflow losses to aquifers, which could impact global water access and ecosystems that rely on rivers.

  PublisherOA PDFDOI

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

  Nature · 2024 · 533 citations

  1st authorCorresponding
  • 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

• The changing nature of groundwater in the global water cycle

  Science · 2024-02-29 · 399 citations

  articleOpen access

  In recent decades, climate change and other anthropogenic activities have substantially affected groundwater systems worldwide. These impacts include changes in groundwater recharge, discharge, flow, storage, and distribution. Climate-induced shifts are evident in altered recharge rates, greater groundwater contribution to streamflow in glacierized catchments, and enhanced groundwater flow in permafrost areas. Direct anthropogenic changes include groundwater withdrawal and injection, regional flow regime modification, water table and storage alterations, and redistribution of embedded groundwater in foods globally. Notably, groundwater extraction contributes to sea level rise, increasing the risk of groundwater inundation in coastal areas. The role of groundwater in the global water cycle is becoming more dynamic and complex. Quantifying these changes is essential to ensure sustainable supply of fresh groundwater resources for people and ecosystems.

  PublisherOA PDFDOI

Recent grants

• CAREER: How streamflow ages vary downstream along river courses

  NSF · $724k · 2021–2026

Frequent coauthors

• Jeffrey J. McDonnell

  University of Birmingham

  33 shared

• Debra Perrone

  University of California, Santa Barbara

  30 shared

• James W. Kirchner

  University of California, Berkeley

  27 shared

• Tom Gleeson

  University of Victoria

  21 shared

• Elco Luijendijk

  University of Bergen

  16 shared

• Richard G. Taylor

  University College London

  15 shared

• J. M. Welker

  University of Alaska Anchorage

  15 shared

• J. J. Gibson

  14 shared

Labs

• Scott Jasechko's LabPI

  Water Resources

Awards & honors

• Kohout Early Career Award from the Geological Society of Ame…
• Hydrologic Sciences Early Career Award from the American Geo…
• CAREER Award from the National Science Foundation (2021)
• Macelwane Medal from the American Geophysical Union (2022)