USGS Groundwater Information: Branch of Geophysics
Complete PDF version of this document (2.6MB PDF)
John W. Lane, Jr.
John H. Williams
Carole D. Johnson
U.S. Geological Survey, Storrs, CT, USA
The characterization of ground-water flow in fractured-rock is a challenging problem. In 1989, the U.S. Geological Survey (USGS), under the Toxic Substance Hydrology Program, established a fractured-rock research site in the Mirror Lake watershed at the Hubbard Brook Experimental Forest, Grafton County, New Hampshire. The goals of this project were to study the processes that control the fate and transport of chemicals in fractured rock over scales from tens of meters to kilometers, apply a multidisciplinary ap-proach to the problem, and develop field methods that could be transferred to other fractured-rock sites. As part of this work, several geophysical methods were developed or tested and an approach evolved for the integrated use of these methods. The overall multidis-ciplinary approach to characterizing fractured rock is described in Shapiro et al. (1999) and a general outline of this process is shown in Figure 1. This abstract dis-cusses the application of surface- and borehole-geophysical methods in the characterization of ground-water flow in fractured rock. Surface geophysical methods provide site reconnaissance suitable for the development of initial conceptual models of ground-water flow in the formation and the siting of test drilling. Conventional borehole-geophysical logs, borehole imag-ing, and advanced single- and cross-hole geophysical methods can be interpreted to identify the location and physical characteristics of fractures, and, potentially, their hydraulic properties. Integration of surface- and borehole-geophysical data with geologic, hydrologic, and geochemical data provides a means for development of a comprehensive interpretation of the hydrogeologic condi-tions at a site and a conceptual understanding of ground-water flow.
Final copy as submitted to Fractured Rock 2001 for publication as: Haeni, F.P., Lane, J.W. Jr., Williams, J.W., and Johnson, C.D., 2001, Use of a geophysical toolbox to characterize ground-water flow in fractured rock: in Fractured Rock 2001 Conference, Proceedings, Toronto, Ontario, March 26-28, 2001, CD-ROM.
free Adobe Acrobat Reader to view PDF files at the Adobe web site.
Visit http://access.adobe.com for free tools that allow visually impaired users to read PDF files.