HR: 15:20h
AN: H43I-07    [Abstracts]
TI: Flow and Transport in Fractured Porous Sandstone: Experimentation and Modeling at Aquifer-Analog Scale
AU: * Weede, M
EM: weede@agk.uka.de
AF: Department of Applied Geology, Karlsruhe University, Kaiserstr. 12, Karlsruhe, 76128 Germany
AU: H\"otzl, H
EM: heinz.hoetzl@agk.uni-karlsruhe.de
AF: Department of Applied Geology, Karlsruhe University, Kaiserstr. 12, Karlsruhe, 76128 Germany
AB: The reliability of numerical models for the prediction of flow and contaminant solute transport in fractured porous aquifers is very limited due to the high structural complexity of these systems. Both the influence of the fracture orientation on flow and transport processes and the varying participation of advective, dispersive, diffusive, and sorptive transport mechanisms can hardly be parameterized. With the realization of in situ flow and tracer experiments at a completely sealed, natural aquifer cutout of about 200 m$^3$ volume, both flow and transport parameters can be evaluated under controlled boundary conditions. The rock at the test site is a highly porous and densely fractured Triassic sandstone. Thus, the diffusive interactions between fracture and rock matrix are intensified and can be experimentally investigated more easily. Primary field studies provide information not only about the basic rock parameters as porosity and rock permeability. Also the statistical fracture orientation, fracture distance distribution and fracture length distribution are determined. By choosing a radial symmetrical borehole arrangement in the center part of the fractured porous sandstone, comparable flow and transport experiments can be conducted at 42 different borehole-to-borehole connections and in twelve different directions. Thus a statistical rating of each flow direction concerning permeability, travel times, maximum concentration and retardation effects is made possible. The measured transport processes can also be judged in terms of dispersion lengths and the participation of diffusive processes by the application of analytical analysis. Furthermore, interactions of different preferred flow channels inside the natural fractured system may be identified. The experimentally measured breakthrough curves are finally used for the calibration and validation of different numerical model concepts.
UR: http://www.agk.uni-karlsruhe.de/projekte/projekte\_hydro/aquiferanalog.html
DE: 5104 Fracture and flow
DE: 5139 Transport properties
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting