#2023 CUAHSI Biennial Colloquium

Poster-Presentation

Title: Access and suitability of fossil aquifers in the United States (Poster #29)


Authors: Merhawi GebreEgziabher (Website: https://www.mgebreegziabher.com/ Email: gebremichael@ucsb.edu)

  Scott Jasechko (Website: https://bren.ucsb.edu/people/scott-jasechko Email: jasechko@bren.ucsb.edu), and 

  Debra Perrone (Website: https://es.ucsb.edu/debra-perrone Email: perrone@ucsb.edu), 


Affiliation: Bren School of Environmental Science and Management, United States (SJ & MG), and Environmental Studies Program, University of California Santa Barbara, United States (DP)

Abstract:

Fossil groundwater, groundwater that was recharged more than 12,000 years ago, is an important water resource across the United States. Despite its importance, fossil groundwater quantity and quality remain imperfectly understood due to uncertainties in the spatial distributions of various aquifer conditions and in groundwater level responses to long-term pumping. Nevertheless, there is no comprehensive analysis of the prevalence and usage of fossil groundwater at a continental scale. To understand environmental controls on fossil groundwater distributions, we (1) digitized the boundaries of aquifer systems and developed a new ‘US Aquifer Database’, (2) confirmed the presence of fossil groundwaters by reviewing primary literature, and (3) analyzed millions of well drilling records and hundreds-of-thousands groundwater level time series in monitoring wells. We show that wells drilled deep enough to tap fossil groundwater are widespread and increasing in number. Our analysis reveals that areas accessing fossil groundwater are not necessarily linked to areas experiencing depletion, reinforcing that groundwater age is not linked directly to sustainability. Many, but not all, fossil aquifers exemplify long term stability in groundwater levels, a stability likely arising due to local hydrological and geological conditions, climate variations, and land uses. 

More to see: 

       PDF Files of fossil groundwater publication in Nature Communications: https://www.nature.com/articles/s41467-022-29678-7

PDF Files of modern groundwater publication in Nature Communications: https://www.nature.com/articles/s41467-022-32954-1 

      US Aquifer Database: https://www.hydroshare.org/resource/d2260651b51044d0b5cb2d293d21af08/ 

      US Aquifer Database Story Map: https://storymaps.arcgis.com/stories/a91f061759e64e44af38daf6cefa4259 

Acknowledgment: 

This material is based upon work supported by the National Science Foundation under Grant No. EAR-2048227. We thank the University of California Santa Barbara.