Characterizing The Relationship Between Evapotranspiration and Groundwater Decline Across Arid Agricultural Regions
Groundwater is the primary water source for irrigated agriculture in many arid regions. Consequently, groundwater declines in cultivated drylands can threaten the sustainability of irrigation. However, little is known about why groundwater levels decline rapidly in some areas and more slowly in others. Here, we develop an accessible and reproducible workflow that integrates open-source, high-resolution data for groundwater-level records, evapotranspiration, and precipitation data to explore the relationship between agriculture and groundwater decline. We show that groundwater declines tend to be most rapid in areas where evapotranspiration exceeds precipitation. Our finding holds across multiple agricultural regions, spanning from southern California to eastern Arkansas. Our results suggest that regions where evapotranspiration exceeds precipitation are at elevated risk of groundwater depletion, and could be good areas to intensify future monitoring efforts. Altogether, our analyses demonstrate how climate and satellite data can be useful predictors of groundwater decline in cultivated drylands, and may provide a promising proxy for groundwater withdrawals where well metering data is absent.
Acknowledgements
We are especially grateful for our client and faculty advisor:
Dr. Scott Jasechko, Professor, Bren School of Environmental Science & Management
We also thank the following individuals for their support:
Dr. Carmen Galaz García, Assistant Teaching Professor
Alicia (Allie) Caughman, Teaching Assistant, Ph.D. Student
Dr. Ashley Larsen, Associate Professor
Andrew (Andy) MacDonald, Assistant Professor
OpenET
Lydia Bleifuss, Program Manager
Alberto Guzman, Senior Software Engineer with NASA Ames Research Center and CSU
Monterey Bay, through the NASA ARC-CREST agreement
Jack and Laura Dangermond Preserve:
The Nature Conservancy (TNC):
Moses Katkowski, Dangermond Preserve Director
Emily Alonso, Dangermond Preserve Visitation Coordinator