HR: 0800h
AN: H51E-01    [Abstracts]
TI: A Modeling Study Using Oscillatory Pressure Waves for Hydraulic Tomography
AU: * McElwee, C D
EM: cmcelwee@ku.edu
AF: University of Kansas Department of Geology, 1475 Jayhawk Blvd., Lawrence, KS 66045, United States
AU: Wachter, B J
EM: bjwach@ku.edu
AF: University of Kansas Department of Geology, 1475 Jayhawk Blvd., Lawrence, KS 66045, United States
AB: We have been doing experimental field work using oscillatory pressure waves to investigate the hydraulic conductivity distribution between source and receiver wells. Theory for a homogeneous aquifer predicts that the amplitude should decay exponentially with radial distance and the phase shift should increase linearly with radial distance. Both the exponential decay coefficient and the phase shift should vary inversely with the square root of the hydraulic conductivity. Extension of this simple theory to heterogeneous aquifer systems suggests the hydraulic conductivity should be replaced with the spatially averaged value. Most of our presented experimental work to date has used horizontal ray paths. Recently, diagonal ray path data has been collected for use in a tomographic reconstruction of the hydraulic conductivity distribution. We are faced with how to process this data effectively. This paper presents the results of modeling studies to evaluate the potential of this method. First, we look at the capability of extending the simple homogeneous analytical solutions to heterogeneous situations. Modeling studies are necessary because we do not have analytical solutions for general heterogeneous situations. The modeling work indicates a useful extension of the homogeneous formulas is possible, making interpretation of the heterogeneous data more efficient. We also deal with resolution issues by considering: what is the minimum detectable zone of heterogeneity? The effect of an upper or lower barrier boundary on the interpretation of the data is also presented. In summary, the use of oscillatory pressure waves for hydraulic tomographic reconstruction of hydraulic conductivity distributions looks promising. This work funded by the Strategic Environmental Research and Development Program (SERDP) as project ER-1367.
DE: 1846 Model calibration (3333)
DE: 1847 Modeling
DE: 1869 Stochastic hydrology
DE: 1894 Instruments and techniques: modeling
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Joint Assembly