HR: 0800h
AN: H51A-0337    [Abstracts]
TI: The behavior of tracer tests in aquifers with noninteger flow dimension
AU: * Cello, P A
EM: cello@uiuc.edu
AF: University of Illinois, Urbana-Champaign, Hydrosystems Laboratory 205 N. Mathews, Urbana, IL 61801 United States
AU: Walker, D D
EM: ddwalker@uiuc.edu
AF: Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL 61820 United States
AU: Valocchi, A J
EM: valocchi@uiuc.edu
AF: University of Illinois, Urbana-Champaign, Hydrosystems Laboratory 205 N. Mathews, Urbana, IL 61801 United States
AU: Loftis, B
EM: bruce@ncsa.uiuc.edu
AF: Rosen Center for Advanced Computing, Purdue University, 302 W. Wood Street, W. Lafayette, IN 47907 United States
AB: The Generalized Radial Flow interpretation of hydraulic tests infers an additional parameter, the flow dimension, to describe the geometry of groundwater flow in highly heterogenous aquifers. Although the intuitive value of the flow dimension is the same as the Euclidean dimension of the aquifer, some models of aquifer heterogeneity produce fields with flow dimensions that are less than the Euclidean dimension. This study examines the behavior and variability of advective transport in stochastic models of highly heterogeneous fields of hydraulic conductivity versus their flow dimension. This is accomplished through Monte Carlo analysis of numerical models simulating converging flow tracer tests in two-dimensional systems. The study results indicate that multivariate Gaussian and fractional Brownian motion models tend to have flow dimensions of n = 2. Corresponding simulations of converging flow tracer tests (CFTT) influenced by matrix diffusion showed late-time breakthrough curves (BTC) with log-log slopes of -3/2, as found by other investigators for the case of matrix diffusion. In contrast, the results suggest that a CFTT in a percolation network model (where the flow dimension is less than the Euclidean dimension) tends to have late-time BTC with log-log slopes of -5/4. These results suggest that the flow dimension may be a useful diagnostic for selecting models of heterogeneity, and that flow dimensions n ≠ 2 may be associated with unique tracer behavior.
DE: 1828 Groundwater hydraulics
DE: 1832 Groundwater transport
DE: 1869 Stochastic hydrology
DE: 4440 Fractals and multifractals
DE: 5114 Permeability and porosity
SC: Hydrology [H]
MN: Fall Meeting 2005