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Tracking the Subsurface Signal of Decadal Climate Warming to Quantify Vertical Groundwater Flow Rates
Author(s) -
Bense V. F.,
Kurylyk B. L.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076015
Subject(s) - groundwater , hydrogeology , groundwater flow , inflection point , borehole , environmental science , geology , global warming , hydrology (agriculture) , inversion (geology) , climate change , soil science , aquifer , geomorphology , geotechnical engineering , oceanography , geometry , mathematics , structural basin
Sustained ground surface warming on a decadal time scale leads to an inversion of thermal gradients in the upper tens of meters. The magnitude and direction of vertical groundwater flow should influence the propagation of this warming signal, but direct field observations of this phenomenon are rare. Comparison of temperature‐depth profiles in boreholes in the Veluwe area, Netherlands, collected in 1978–1982 and 2016 provided such direct measurement. We used these repeated profiles to track the downward propagation rate of the depth at which the thermal gradient is zero. Numerical modeling of the migration of this thermal gradient “inflection point” yielded estimates of downward groundwater flow rates (0–0.24 m a −1 ) that generally concurred with known hydrogeological conditions in the area. We conclude that analysis of inflection point depths in temperature‐depth profiles impacted by surface warming provides a largely untapped opportunity to inform sustainable groundwater management plans that rely on accurate estimates of long‐term vertical groundwater fluxes.