Application of a mixing cell model to describe contaminant transport - An example of appropriate technology

The Uranium Mill Tailings Remedial Action (UMTRA) Project is undertaking remedial actions at designated inactive uranium mill sites. The mill tailings lie within an alluvial floodplain adjacent to the Colorado River. Mancos Shale with hydraulic conductivity of 5x10/sup -4/ to 2x10/sup -7/ cm/sec lies below four to more than six meters (13.1 to 19.7 feet) of alluvium. The mill site is surrounded by industry and residences of the city of Grand Junction. Ground water in the alluvium flows generally parallel to the Colorado River with the Colorado River adjacent to the mill site being an effluent stream during the fall and winter and an influent stream during the spring snowmelt runoff. In the vicinity of the tailings, the saturated thickness of the alluvium ranges from less than 3.05, meters (10 feet) to more than 6.10 meters (20 feet). Portions of the tailings are below the water table