HR: 0800h
AN: H21C-1359    [Abstracts]
TI: Estimating Hydraulic Conductivity: Hydraulic Tomography and High-Resolution Slug Tests
AU: * Engard, B
EM: brengard@ku.edu
AF: University of Kansas, Dept. of Geology, 1475 Jayhawk Blvd., Lawrence, KS 66045 United States
AU: McElwee, C D
EM: cmcelwee@ku.edu
AF: University of Kansas, Dept. of Geology, 1475 Jayhawk Blvd., Lawrence, KS 66045 United States
AB: The hydraulic conductivity distribution is one of the main controls on subsurface flow, affecting all aspects including maximum well yields, spatial extent of contamination, and effectiveness of remediation. Research to develop and improve methods for characterizing the hydraulic conductivity distribution continues to be a high priority. Typical methods used to determine K include pumping tests, which give average values over large volumes, and high-resolution slug tests, which give detailed information near a well. The research presented here uses a continuous, controlled, sinusoidal pressure signal at the source well and measures the signal at various depths in an observation well located at some known radial distance. Simple theory predicts that the phase and log amplitude (after correction for radial spreading) of the sinusoidal signal should vary linearly with the hydraulic diffusivity and radial distance from the source well. Estimates of a spatially averaged diffusivity [ratio of hydraulic conductivity (K) to specific storage (Ss)] between wells can then be determined from the signal attenuation and phase shift at the measured depths. In addition, the vertical hydraulic conductivity profiles at the source and receiver wells can be measured with high-resolution slug testing. Preliminary data suggests that sinusoidal signal propagation occurs over reasonable distances and, therefore, provides average well to well estimates of the spatial distribution of diffusivity at various depths, which correlate well with the high-resolution slug test data at the source and receiver wells. The simplest interpretation would be to use a linear extrapolation of the high-resolution slug test data between wells to see if that explains the field data for sinusoidal amplitude decay and phase shift. It may be that more sophisticated processing, perhaps using numerical models, will allow better delineation of the inter-well hydraulic conductivity. This research was supported in part by the U.S. Department of Defense, through the Strategic Environmental Research and Development Program (SERDP).
DE: 1828 Groundwater hydraulics
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1835 Hydrogeophysics
SC: Hydrology [H]
MN: Fall Meeting 2005