HR: 1340h
AN: H23G-1711    [Abstracts]
TI: Dispersion Analysis Using Particle Tracking Simulations Through Heterogeneity Based on Outcrop Lidar Imagery
AU: * Klise, K A
EM: kaklise@sandia.gov
AF: Sandia National Laboratories, Geohydrology Department PO Box 5800, MS 0735, Albuquerque, NM 87185-0735, United States
AU: Weissmann, G S
EM: weissman@unm.edu
AF: University of New Mexico, Earth and Planetary Sciences, MSCO3 2040 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
AU: McKenna, S A
EM: samcken@sandia.gov
AF: Sandia National Laboratories, Geohydrology Department PO Box 5800, MS 0735, Albuquerque, NM 87185-0735, United States
AU: Tidwell, V C
EM: vctidwe@sandia.gov
AF: Sandia National Laboratories, Geohydrology Department PO Box 5800, MS 0735, Albuquerque, NM 87185-0735, United States
AU: Frechette, J D
EM: jdfrech@unm.edu
AF: University of New Mexico, Earth and Planetary Sciences, MSCO3 2040 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
AU: Wawrzyniec, T F
EM: tfw@unm.edu
AF: University of New Mexico, Earth and Planetary Sciences, MSCO3 2040 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
AB: Solute plumes are believed to disperse in a non-Fickian manner due to small-scale heterogeneity and variable velocities that create preferential pathways. In order to accurately predict dispersion in naturally complex geologic media, the connection between heterogeneity and dispersion must be better understood. Since aquifer properties can not be measured at every location, it is common to simulate small-scale heterogeneity with random field generators based on a two-point covariance (e.g., through use of sequential simulation algorithms). While these random fields can produce preferential flow pathways, it is unknown how well the results simulate solute dispersion through natural heterogeneous media. To evaluate the influence that complex heterogeneity has on dispersion, we utilize high-resolution terrestrial lidar to identify and model lithofacies from outcrop for application in particle tracking solute transport simulations using RWHet. The lidar scan data are used to produce a lab (meter) scale two-dimensional model that captures 2-8 mm scale natural heterogeneity. Numerical simulations utilize various methods to populate the outcrop structure captured by the lidar-based image with reasonable hydraulic conductivity values. The particle tracking simulations result in residence time distributions used to evaluate the nature of dispersion through complex media. Particle tracking simulations through conductivity fields produced from the lidar images are then compared to particle tracking simulations through hydraulic conductivity fields produced from sequential simulation algorithms. Based on this comparison, the study aims to quantify the difference in dispersion when using realistic and simplified representations of aquifer heterogeneity. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
DE: 1832 Groundwater transport
DE: 1847 Modeling
DE: 1859 Rocks: physical properties
DE: 1869 Stochastic hydrology
SC: Hydrology [H]
MN: 2007 Fall Meeting