TRANSVERSE DISPERSION OF CONTAMINANTS IN FRACTURED PERMEABLE FORMATIONS

Our interest in understanding some of the mechanisms involved in the m ineralization of the Great Bend Prairie aquifer of Kansas by salt wate r originating from Permian bedrock formations, which are fractured san dstones, has prompted this basic study. The fractured permeable format ion is represented by a simplified conceptual model incorporating two sets of oblique and parallel fractures embedded in permeable blocks. T he domain is initially divided into a completely freshwater zone overl ying a completely saline water zone. However, the sharp interface orig inally existing between the saline and fresh water is subject to dispe rsion because of mixing in fracture intersections and between the frac ture flow and the permeable block flow. Simulations based on the use o f an appropriate numerical model developed in the present study have h elped us to characterize dispersion of the sharp interface and creatio n of the transition zone. Relationships of transverse and longitudinal dispersion in the domain are also determined.