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Interpreting Repeated Temperature‐Depth Profiles for Groundwater Flow
Author(s) -
Bense Victor F.,
Kurylyk Barret L.,
van Daal Jonathan,
van der Ploeg Martine J.,
Carey Sean K.
Publication year - 2017
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr021496
Subject(s) - borehole , hydrogeology , advection , groundwater flow , groundwater , geology , transient (computer programming) , soil science , flow (mathematics) , environmental science , hydrology (agriculture) , mechanics , geotechnical engineering , aquifer , thermodynamics , physics , computer science , operating system
Temperature can be used to trace groundwater flows due to thermal disturbances of subsurface advection. Prior hydrogeological studies that have used temperature‐depth profiles to estimate vertical groundwater fluxes have either ignored the influence of climate change by employing steady‐state analytical solutions or applied transient techniques to study temperature‐depth profiles recorded at only a single point in time. Transient analyses of a single profile are predicated on the accurate determination of an unknown profile at some time in the past to form the initial condition. In this study, we use both analytical solutions and a numerical model to demonstrate that boreholes with temperature‐depth profiles recorded at multiple times can be analyzed to either overcome the uncertainty associated with estimating unknown initial conditions or to form an additional check for the profile fitting. We further illustrate that the common approach of assuming a linear initial temperature‐depth profile can result in significant errors for groundwater flux estimates. Profiles obtained from a borehole in the Veluwe area, Netherlands in both 1978 and 2016 are analyzed for an illustrative example. Since many temperature‐depth profiles were collected in the late 1970s and 1980s, these previously profiled boreholes represent a significant and underexploited opportunity to obtain repeat measurements that can be used for similar analyses at other sites around the world.