Where the fractures are open and interconnected, a portion of the network can conduct groundwater flow, and especially so over the short time scales associated with the extraction or injection of fluids in a bedrock well. Despite the importance of individual conductive fractures within the network, fractures are generally poorly characterized in most groundwater studies, because of the inaccessibility of interwell fractures to direct observation and to the inability of surface and crosshole geophysical methods to image individual fractures and fracture networks to the same degree of detail they can be mapped on surface exposures. Borehole pump tests reveal pods of high fracture permeability imbedded in a low permeability fractured rock matrix. 3 dimensional discrete fracture network models, conditioned by the statistics of fracture properties measured in roadcuts and boreholes, are constructed to simulate the undetectable fracture network throughout the volume of rock. Click on figure to zoom in Click on figure to zoom in Geologists' Brunton Compass is used to measure the orientation of fractures.
Tapered gauge is used to measure maximum fracture aperture.
Contour gauge is used to measure roughness profile of a fracture surface. Contoured lower hemi-sphere projection of poles to fractures. Contour interval 1.0 Histogram of aperture frequency for fractures. A perfectly flat surface has a RC value of 0. A very rough surface has a RC of 20.