THE USE OF DISCRETE FRACTURE NETWORK MODELING TOOLS FOR DEFINING STOCHASTIC ZOC’S IN FRACTURED ROCK

Delineation of ZOC’s for pumping wells is a difficult and critical issue facing managers needing to protect water resources when the hydrology of the aquifer is dominated by fracture flow. It may be a mistake to believe that the ZOC is approximated by some ellipsoidal pattern around the well or wells. Particularly where the fracturing has resulted from folding of the rock, the pattern can lead to quite complex drainage patterns. Tools based on discrete fracture network modeling can be used to both more realistically delineate the ZOC’s around a well or group of wells, and can also easily incorporate the uncertainty inherent in the underlying fracture network. This results in maps that show the probability of an area being part of the ZOC of the well or well field. This paper will illustrate how to define these stochastic ZOC’s using discrete fracture network modeling tools, and illustrate the geometry of ZOC’s as inferred from these models and tracer tests in fractured rock.