Groundwater drought in the United States: Spatial and temporal variability

Journal of Hydrology
By: , and 

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Abstract

Many communities and ecosystems in the United States that are dependent on groundwater are potentially adversely affected by groundwater drought. We computed yearly groundwater-drought metrics and mean groundwater levels at well locations across the conterminous United States (CONUS), using data from wells and remotely sensed and modeled Gravity Recovery and Climate Experiment Drought Monitor Data Assimilation (GRACE-DADM). We also modeled the probability of low or high human impact at each well location. The spatial distribution of groundwater-drought duration and severity from 2001 to 2020 for 1,510 wells shows longer maximum duration and higher maximum severity events in drier regions like the Southwest than in wetter regions like the Northeast. Based on 613 wells in CONUS from 1981 to 2020, there are many significant decreases in drought duration and severity in the Northeast and many significant increases in annual-mean groundwater levels. In contrast, there are many significant increases in drought metrics and decreases in mean water levels in parts of the Southeast. There are major differences in trends from 2001 to 2020 between well-based and GRACE-DADM-based groundwater metrics in some CONUS regions and a very low correlation between trends at individual locations across CONUS. A potential reason for this disparity is the low GRACE-DADM resolution (∼12 km) and the potential for a large amount of groundwater variation at the local scale. Also, GRACE-DADM represents shallow, unconfined aquifers which may not match the screened interval of the monitoring wells we evaluated. Large spatial gaps in long-term, high frequency, and quality-assured groundwater-well monitoring data present a challenge for understanding groundwater-drought variability across CONUS. Remote sensing tools such as GRACE can help but cannot fully replace well monitoring, as highlighted by our study results. Substantially more long-term monitoring wells would more accurately represent groundwater-drought trends and spatial variability across CONUS, particularly in western regions.

Suggested Citation

Hodgkins, G., Simeone, C., Lombard, M.A., Caldwell, T., Hammond, J., Wieczorek, M., and Dudley, R., 2026, Groundwater drought in the United States: Spatial and temporal variability: Journal of Hydrology, v. 671, 135180, 18 p., https://doi.org/10.1016/j.jhydrol.2026.135180.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Groundwater drought in the United States: Spatial and temporal variability
Series title Journal of Hydrology
DOI 10.1016/j.jhydrol.2026.135180
Volume 671
Publication Date March 11, 2026
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) New England Water Science Center
Description 135180, 18 p.
Country United States
Other Geospatial conterminous United States
Additional publication details