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Continental-scale analysis of shallow and deep groundwater contributions to streams

March 4, 2021

Groundwater discharge generates streamflow and influences stream thermal regimes. However, the water quality and thermal buffering capacity of groundwater depends on the aquifer source-depth. Here, we pair multi-year air and stream temperature signals to categorize 1729 sites across the continental United States as having major dam influence, shallow or deep groundwater signatures, or lack of pronounced groundwater (atmospheric) signatures. Approximately 40% of non-dam stream sites have substantial groundwater contributions as indicated by characteristic paired air and stream temperature signal metrics. Streams with shallow groundwater signatures account for half of all groundwater signature sites and show reduced baseflow and a higher proportion of warming trends compared to sites with deep groundwater signatures. These findings align with theory that shallow groundwater is more vulnerable to temperature increase and depletion. Streams with atmospheric signatures tend to drain watersheds with low slope and greater human disturbance, indicating reduced stream-groundwater connectivity in populated valley settings.

Publication Year 2021
Title Continental-scale analysis of shallow and deep groundwater contributions to streams
DOI 10.1038/s41467-021-21651-0
Authors D. Hare, A. M. Helton, Zachary C. Johnson, John W. Lane, Martin A. Briggs
Publication Type Article
Publication Subtype Journal Article
Series Title Nature Communications
Index ID 70218771
Record Source USGS Publications Warehouse
USGS Organization Utah Water Science Center; WMA - Earth System Processes Division