HR: 15:10h
AN: H13G-07    [Abstracts]
TI: Flow-Channeling in Fractured Bedrock: Combining GPR, Tracer, and Hydraulic Data
AU: * Becker, M W
EM: mwbecker@geology.buffalo.edu
AF: Dept of Geology, University at Buffalo, SUNY, 876 NSC, Buffalo, NY 14260 United States
AU: Talley, J
EM: jltalley@buffalo.edu
AF: Dept of Geology, University at Buffalo, SUNY, 876 NSC, Buffalo, NY 14260 United States
AU: Baker, G S
EM: gbaker@geology.buffalo.edu
AF: Dept of Geology, University at Buffalo, SUNY, 876 NSC, Buffalo, NY 14260 United States
AU: Beyrle, N
EM: nbeyrle@buffalo.edu
AF: Dept of Geology, University at Buffalo, SUNY, 876 NSC, Buffalo, NY 14260 United States
AB: Channeling of flow in a fracture plane has long been hypothesized, but never observed in map view. In a series of recent experiments, Ground Penetrating Radar (GPR) reflections were used to track the migration of saline tracer through a single saturated horizontal fracture in sandstone bedrock near Altona New York. Reflection amplitudes increased significantly in the presence of saline tracer. Tracer movement was mapped at multiple points in time over an approximately 100 square meter grid. Both forced and natural gradient transport experiments were conducted. In forced gradient experiments, saline tracer swept an area that was much smaller than would be predicted for a homogeneous conductivity field. Tracer also moved in a very heterogeneous manner under the influence of a natural hydraulic gradient. Hydraulic response in wells and tracer breakthrough compare favorably with the distribution of GPR-mapped saline fluid. These preliminary results suggest that the concept of channeled flow in rock fractures is valid, but specific channeling behavior is highly dependent upon hydraulic forcing. This combination of GPR, tracer, and hydraulic information may help develop better methods for measuring effective porosity through fractured bedrock.
UR: http://www.geology.buffalo.edu/Research/hydro/
DE: 5104 Fracture and flow
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 0694 Instrumentation and techniques
DE: 0994 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting