HR: 13:55h
AN: H52B-02 [PDF]
TI: Fanay-Augres Revisited: Stochastic Continuum Modeling of Flow and Transport in a Crystalline Rock
Mass
AU: Ando, K
EM: k-ando@rwmc.or.jp
AF: Obayashi Corporation, Shinagawa Intercity Tower B, 2-15-2, Konan, Minato-ku, Tokyo, 108-8502
Japan
AU: Kostner, A
EM: albert.kostner@omv.com
AF: Unknown, Unknown, Hinterbruhl, Unknown
Austria
AU: * Neuman, S P
EM: neuman@hwr.arizona.edu
AF: University of Arizona, Department of Hydrology, Tucson, AZ 85721 United States
AB:
A stochastic discrete-fracture model was used by Cacas et al.(1990a-b) to interpret flow measurements and transport
experiments in a fractured crystalline rock mass at Fanay-Augres. They considered continuum models to be incapable of
properly interpreting small-scale measurements or tracer tests in fractured systems, which in their view require
three-dimensional modeling of numerous discrete channels; in their opinion, continuum modeling applies only to average flow
on a relatively large scale. Cacas et al. considered their discrete fracture model to have been validated by its demonstrated
ability to reproduce selected experimental results. In this paper flow and transport at Fanay-Augres are modeled by viewing
the fractured rock as a stochastic continuum in a manner originally proposed by Neuman (1987). The stochastic continuum
approach obviates the need for detailed information about fracture geometry or assumptions about how individual fractures
control flow and transport. All it requires is the delineation of a few dominant features, which can be embedded into the
stochastic continuum model as heterogeneous porous slabs. Though a fault zone has been identified at the Fanay-Augres
experimental site, it has been modeled neither by Cacas et al. nor in this paper. In fact, in this paper a larger selection
of experimental results than those considered by Cacas et al. are reproduced merely by modeling the rock as a statistically
homogeneous continuum in two dimensions. These results demonstrate that a continuum approach may be well suited for the
analysis of flow and transport in fractured rock. This does not constitute a validation of the continuum approach, just as
the results of Cacas et al. fall short of validating the discrete fracture approach. Instead, the two sets of results
illustrate jointly the well-established principle that an open system, especially one as complex as fractured hydrogeologic
environments tend to be, cannot be described uniquely on the basis of sparse data and need not be described in great detail
to capture its salient behavior by a model.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1869 Stochastic processes
DE: 3210 Modeling
SC: Hydrology [H]
MN: 2003 Fall Meeting