Hydrologic Characterization of Repository Sites in Fractured Rock

The history of the development of techniques for determining equivalent rock mass permeability from discrete fracture data is reviewed. These techniques began with conceptual models which considered all fractures to be infinitely long. Because fractures are in fact finite, the equivalent permeability tensor computed by this approximation may not be applicable. Recent studies of the definition of an equivalent permeability tensor for networks of fractures with finite lengths are reviewed, and field techniques which show promise for obtaining in situ measurements of fracture length are presented.