HR: 0800h
AN: H11C-0660    [Abstracts]
TI: Characterizing the Response of an Unconfined Aquifer to Pumping with Borehole Ground Penetrating Radar
AU: * Ferre, T P
EM: ty@hwr.arizona.edu
AF: University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721-0011, United States
AU: Vrugt, J A
EM: laf107@hotmail.com
AF: Los Alamos National Laboratory, Mail Stop T003, Los Alamos, NM 87545, United States
AU: von Glinski, G
EM: gvonglin@hwr.arizona.edu
AF: University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721-0011, United States
AU: Hinnell, A C
EM: andrew@hwr.arizona.edu
AF: University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721-0011, United States
AB: Paired measurements of water table elevation and water content profiles were collected within the combined zone of influence of three pumped wells during pumping and recovery. Water content profiles were measured using zero offset borehole ground penetrating radar (BGPR). This electromagnetic method gives high-resolution (25 cm) rapid (<10 seconds per depth) measurements. But, each water content measurement represents an average over a 1 m depth interval. To analyze the hydrologic response, a one dimensional water flow model was coupled with a BPGR instrument response model. The flow model predicted the water content profile with time, using the water table elevation as a time-varying lower boundary condition and a zero flux ground surface boundary condition. The hydrologic and petrophysical parameters in the flow and instrument model were simultaneously optimized with the Shuffled Complex Evolution Metropolis stochastic optimization algorithm using the difference between predicted and measured BGPR travel times. Results demonstrate that the hydrologic and petrophysical parameters are well constrained by calibration against measured BPGR travel times. Moreover, we sequentially estimated the hydraulic properties that apply during pumping and recovery, providing a field demonstration of hysteresis. The results also quantify both the timing and location of delayed drainage during pumping and recovery in an unconfined aquifer.
DE: 0594 Instruments and techniques
DE: 1835 Hydrogeophysics
DE: 1875 Vadose zone
DE: 1894 Instruments and techniques: modeling
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting