No Well? No Problem: Investigating the Capability of Time-Domain Electromagnetics to Infer Aquifer Properties in Place of a Monitoring Well
Chloe Codner1, Guy Wall1, Iosif Xiradakis1, Natalie Yurek1, Neha Gupta2, Stefano Nerozzi3, T.P.A. Ferré1, Jacob Taylor3
1Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ
2Arizona Institute for Resilience, University of Arizona, Tucson, AZ
3Department of Planetary Sciences, University of Arizona, Tucson, AZ
Sustainable groundwater management begins with a comprehensive understanding of the hydrologic system and their governing properties. Hydrologic investigations are often limited by our ability to quantify subsurface behaviors, but geophysical methods like time-domain electromagnetics (TDEM) have provided a means for for imaging the subsurface extent of groundwater resources. Data collected from TDEM surveys has proven valuable for forming geologic models to serve as the basis for groundwater flow models and reducing the uncertainty of estimated aquifer properties. This study aims to evaluate the spatial sensitivity of the TDEM instrument to further understand the capabilities of this method for hydrologic investigation. Using a forward modeling approach with the SimPEG Python framework, the response of the TDEM instrument will be simulated for changing subsurface conditions. These conditions are intended to replicate the behavior of the subsurface during a pumping test to understand how the spatially averaged response of the instrument could be used to constrain aquifer property parameters which normally require point measurements collected from nearby monitoring wells. Forward model results will be compared to data collected during an unconfined aquifer pumping test to examine differences between modeled and observed responses, but the majority of our work will focus on virtual pumping tests. The results of this sensitivity analysis can help to determine whether TDEM can function as an alternative to traditional pumping tests and provide a noninvasive, rapid technique for approximating aquifer properties.