HR: 1340h
AN: H33D-1612    [Abstracts]
TI: Sinusoidal Testing of Multi-Layer Aquifers
AU: * Rasmussen, T
EM: trasmuss@uga.edu
AF: The University of Georgia, Warnell School of Forestry and Natural Resources, Athens, GA 30602-2152, United States
AU: Bakker, M
EM: Mark.Bakker@tudelft.nl
AF: Delft University of Technology, Water Resources Section, Faculty of Civil Engineering and Geosciences, TU Delft, Stevinweg 1, Delft, 2628 CN, Netherlands
AU: Toll, N J
EM: njtoll@sandia.gov
AF: The University of Georgia, Warnell School of Forestry and Natural Resources, Athens, GA 30602-2152, United States
AB: Sinusoidal aquifer tests can be used to characterize multi-layer aquifers. Three sinusoidal aquifer tests were conducted at the Waste Isolation Pilot Plant near Carlsbad, New Mexico, USA. Aquifer tests were performed by pumping at a variable (periodic) rate and measuring the resulting amplitudes and phases (time delays) of water level fluctuations in nearby observation wells. Aquifer properties for the Upper and Lower Culebra Member are found by fitting a two-layer model to observation-well drawdown data. Aquifer properties are estimated by subdividing the vertical section into multiple layers to provide greater resolution within the aquifer. The problem is approached mathematically using a matrix formulation that employs eigenvalues and eigenvectors to evaluate the resulting Bessel function of complex matrix arguments. Applications using multiple equivalent properties include the need to interpret conditions when pumping is limited to partial penetration, or to conditions when multiple, non-adjacent intervals are pumped. The solution can also be used to interpret tests in aquifers where vertical variations in aquifer properties are expected.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2007 Fall Meeting