HR: 16:00h
AN: H14B-01 INVITED     [Abstracts]
TI: Characterization of retention processes in crystalline rock
AU: * Cvetkovic, V
EM: vdc@kth.se
AF: Royal Institute of Technology, BV 32, Stockholm, SE-10044 Sweden
AB: Tracer transport in randomly fractured porous media results from a combination of random advection and a variety of exchange (retention) processes. A generalized dual porosity model is presented for this coupling, which explicitly accounts for transitional and exchange disorder, and a formal solution is provided; the solution is applicable to both sparsley and densely fractured rocks. Illustration examples are focused on sparsley fractured rocks that are highly heterogeneous and are of prime interest in environmental applications. We study the relative effect of advection and retention heterogeneity on tracer first passage times through a rock volume, comparing our generalized with the classical dual porosity model. The classical model generally underestimates retention significantly. A simple measure and criteria is established for assessing the relative effect of advection and retention heterogeneity. It is found that for tracers with a wide range of retention and decay properties, transport is controlled by retention heterogeneity, with advection heterogeneity being of secondary importance. This finding can have important practical implications for predicting large-scale, long-term tracer transport in fractured geological media.
DE: 5139 Transport properties
DE: 1803 Anthropogenic effects
DE: 1832 Groundwater transport
DE: 1869 Stochastic processes
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting