A field and numerical study of a tracer test in a gypsum formation beneath a road

ABSTRACT: Gypsum dissolution has the potential to create karst and sinkholes which can damage infrastructure. A dye tracer test was conducted between a sinkhole in the Harcus Drain, and a gypsum quarry in the RM of Alonsa, Manitoba, Canada. The aim of this study was to provide insight into the ongoing dissolution along the drain by analyzing groundwater flow properties. Groundwater regionally flows east to Lake Manitoba, however, locally from the drain it flows north toward the quarry. Analysis of tracer breakthrough curves suggested that there is a hydraulic connection between the drain and the quarry, likely resulting from gypsum excavation. As a consequence, dissolution of a gypsum formation in the Harcus Drain, and perhaps, under South Leifur Road are resulting in damage to infrastructure.