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Cross‐validation of geo‐electrical and hydrogeological models to evaluate seawater intrusion in coastal aquifers
Author(s) -
Comte JeanChristophe,
Banton Olivier
Publication year - 2007
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 - 10.1029/2007gl029981
Subject(s) - hydrogeology , electrical resistivity tomography , aquifer , groundwater , geology , electrical resistivity and conductivity , groundwater flow , seawater intrusion , seawater , soil science , geophysics , hydrology (agriculture) , geotechnical engineering , oceanography , engineering , electrical engineering
The validation of variable‐density flow models simulating seawater intrusion in coastal aquifers requires information about concentration distribution in groundwater. Electrical resistivity tomography (ERT) provides relevant data for this purpose. However, inverse modeling is not accurate because of the non‐uniqueness of solutions. Such difficulties in evaluating seawater intrusion can be overcome by coupling geophysical data and groundwater modeling. First, the resistivity distribution obtained by inverse geo‐electrical modeling is established. Second, a 3‐D variable‐density flow hydrogeological model is developed. Third, using Archie's Law, the electrical resistivity model deduced from salt concentration is compared to the formerly interpreted electrical model. Finally, aside from that usual comparison‐validation, the theoretical geophysical response of concentrations simulated with the groundwater model can be compared to field‐measured resistivity data. This constitutes a cross‐validation of both the inverse geo‐electrical model and the groundwater model.