Hydrogeologic Investigation of a Radioactive Waste Management Site in Southern Alberta

Abstract

For the past 2 years, detailed field and laboratory studies have focused on the hydrogeologic investigation of a proposed, subsurface, radioactive waste management site in Alberta at the Defence Research Establishment Suffield. The basic approach has involved test drilling and sampling augmented by down-hole geophysical techniques to establish stratigraphic sequences. In addition, piezometers and soil moisture – temperature blocks have been emplaced to define the saturated–unsaturated flow regime. Laboratory studies of drift and bedrock samples have characterized variations in mineralogy, texture, and sorptive properties.Piezometric data indicate that the site is predominantly a recharge area with median values of permeability ranging from 2.8 × 10−2 to 2.8 × 10−4 ft/day (1 × 10−5 to 1 × 10−7 cm/s). To reach the zone of saturation, recharge water must pass downward through a maximum of 120 ft (36.3 m) of unsaturated, glacial drift with cation exchange capacities ranging from 25 to 105 mequiv per 100 g. The absence of water level fluctuations in observation wells and the soil moisture block data indicate that the quantity of water moving downward through the waste management site is small.