Divergent effects of climate change on future groundwater availability in key mid-latitude aquifers

Nature Portfolio (Springer Nature) | July 24th, 2020

Groundwater provides critical freshwater supply, particularly in dry regions where surface water availability is limited. Climate change impacts on GWS (groundwater stora

Groundwater provides critical freshwater supply, particularly in dry regions where surface water availability is limited. Climate change impacts on GWS (groundwater storage) could affect the sustainability of freshwater resources. Here, we used a fully-coupled climate model to investigate GWS changes over seven critical aquifers identified as significantly distressed by satellite observations. We assessed the potential climate-driven impacts on GWS changes throughout the 21st century under the business-as-usual scenario (RCP8.5). Results show that the climate-driven impacts on GWS changes do not necessarily reflect the long-term trend in precipitation; instead, the trend may result from enhancement of evapotranspiration, and reduction in snowmelt, which collectively lead to divergent responses of GWS changes across different aquifers. Finally, we compare the climate-driven and anthropogenic pumping impacts. The reduction in GWS is mainly due to the combined impacts of over-pumping and climate effects; however, the contribution of pumping could easily far exceed the natural replenishment.

Domestic well vulnerability to drought duration and unsustainable groundwater management in California's Central Valley

Environmental Research Letters (IOP) | March 18th, 2020

Millions of Californians access drinking water via domestic wells, which are vulnerable to drought and unsustainable groundwater management. Groundwater overdraft and th

Millions of Californians access drinking water via domestic wells, which are vulnerable to drought and unsustainable groundwater management. Groundwater overdraft and the possibility of longer drought duration under climate change threatens domestic well reliability, yet we lack tools to assess the impact of such events. Here, we leverage 943,469 well completion reports and 20 years of groundwater elevation data to develop a spatially-explicit domestic well failure model covering California’s Central Valley. Our model successfully reproduces the spatial distribution of observed domestic well failures during the severe 2012–2016 drought (n=2027). Next, the impact of longer drought duration (5–8years) on domestic well failure is evaluated, indicating that if the 2012–2016 drought would have continued into a 6 to 8 year long drought, a total of 4037–5460 to 6538–8056 wells would fail. The same drought duration scenarios with an intervening wet winter in 2017 lead to an average of 498 and 738 fewer well failures. Additionally, we map vulnerable wells at high failure risk and find that they align with clusters of predicted well failures. Lastly, we evaluate how the timing and implementation of different projected groundwater management regimes impact groundwater levels and thus domestic well failure. When historic overdraft persists until 2040, domestic well failures range from 5966 to 10 466 (depending on the historic period considered). When sustainability is achieved progressively between 2020 and 2040, well failures range from 3677 to 6943, and from 1516 to 2513 when groundwater is not allowed to decline after 2020.

Drought and Groundwater Sustainability in California’s Farming Regions

Public Policy Institute of California (PPIC) | June 25th, 2024

Earth’s clouds are shrinking, boosting global warming

American Association for the Advancement of Science (AAAS) | December 19th, 2024

For more than 20 years, NASA instruments in space have tracked a growing imbalance in Earth’s solar energy budget, with more energy entering than leaving the planet. Mu

For more than 20 years, NASA instruments in space have tracked a growing imbalance in Earth’s solar energy budget, with more energy entering than leaving the planet. Much of that imbalance can be pinned on humanity’s greenhouse gases emissions, which trap heat in the atmosphere. But explaining the rest has been a challenge. The loss of reflective ice, exposing darker ground and water that absorb more heat, isn’t enough to explain the deficit, and the decline in light-reflecting hazes as countries clean up or close polluting industry falls short as well. “Nobody can get a number that’s even close,” says George Tselioudis, a climate scientist at NASA’s Goddard Institute for Space Studies.

East Kaweah Groundwater Sustainability Agency 2022 First Amended Groundwater Sustainability Plan

East Kaweah Groundwater Sustainability Agency (EKGSA) | July 27th, 2022

Due to size, this file has been divided into eight parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8

Due to size, this file has been divided into eight parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8

Economic consequences of optimized water management for a prolonged, severe drought in California

American Geophysical Union (AGU) | May 21st, 2010

If abrupt climate change has occurred in the past and may be more likely under human forcing, it is relevant to look at the adaptability of current infrastructure system

If abrupt climate change has occurred in the past and may be more likely under human forcing, it is relevant to look at the adaptability of current infrastructure systems to severe conditions of the recent past. Geologic evidence suggests two extreme droughts in California during the last few thousand years, each 120–200 years long, with mean annual streamflows 40%–60% of the historical mean. This study synthesized a 72-year drought with half of mean historical inflows using random sampling of historical dry years. One synthetic hydrological record is used, and sensitivity to different interpretations of the paleo record is not evaluated. Economic effects and potential adaptation of California’s water supply system in 2020 to this drought is explored using a hydro-economic optimization model. The model considers how California could respond to such an extreme drought using water trading and provides best‐case estimates of economic costs and effects on water operations and demands. Results illustrate the ability of extensive, intertied, and flexible water systems with heterogeneous water demands to respond to severe stress. The study follows a different approach to climate change impact studies, focusing on past climate changes from the paleorecord rather than downscaled general circulation model results to provide plausible hydrologic scenarios. Adaptations suggested for the sustained drought are similar for dry forms of climate warming in California and are expensive but not catastrophic for the overall economy but would impose severe burdens on the agricultural sector and environmental water uses.

Effects of more extreme precipitation regimes on maximum seasonal snow water equivalent

American Geophysical Union (AGU) | October 31st, 2012

This study demonstrates how more extreme precipitation regimes (MEPR) under a changed climate might affect seasonal snow water resources.

This study demonstrates how more extreme precipitation regimes (MEPR) under a changed climate might affect seasonal snow water resources.

Effects of Snow Water Storage on Hydrologic Partitioning Across the Mountainous, Western United States

American Geophysical Union (AGU) | July 12th, 2023

The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If the Snow Stora

The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If the Snow Storage Index (SSI) decreases with future warming, the volume of water partitioned streamflow will decrease non-uniformly across the western U.S. with substantial implications for ecosystemsand agricultural, industrial, and domestic water supplies.

Effects of Surface-Water Use on Domestic Groundwater Availability and Quality During Drought in the Sierra Nevada Foothills, California

U.S. Geological Survey (USGS) | January 13th, 2020

Approximately 2 million California residents rely on privately owned domestic wells for drinking water. During the California drought of 2012−16 groundwater lev

Approximately 2 million California residents rely on privately owned domestic wells for drinking water. During the California drought of 2012−16 groundwater levels declined in many parts of the state and wells were deepened in response. Most of the wells deepened during this time were domestic wells that were drilled into fractured bedrock throughout the Sierra Nevada foothills region of northern California (California Department of Water Resources, 2014). To understand the impacts of extreme drought on groundwater supply availability and quality in this setting, the United States Geological Survey (USGS) completed a geochemical survey of domestic wells throughout the Yuba and Bear River watersheds during 2015–16 (fig. 1) as part of the State Water Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). This fact sheet highlights key findings from the GAMA-PBP assessment (Levy and others, 2020).

Emerging trends in global freshwater availability

Nature Portfolio (Springer Nature) | May 17th, 2018

Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) sat

Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002–2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, climate change or combinations thereof. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango Delta. Others are consistent with climate model predictions. This observation-based assessment of how the world’s water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security.