Relations between hydrogeology and soil characteristics near Deloraine, Manitoba

Abstract

The influence of hydrogeologic factors on genetic soil distributions near Deloraine in southwestern Manitoba was studied during a two year period. Emphasis was placed on determining the detailed hydrogeologic characteristics along a narrow 25 mile long strip of terrain between Turtle Mountain and the Souris Plain. To characterize the hydrogeology, 15 nests of piezometers were installed in the Quaternary and bedrock deposits. Hydraulic head data and samples of the groundwater were obtained from the piezometers. The hydraulic head data, chemistry of the groundwater and knowledge of the stratigraphy were used to interpret the patterns of groundwater flow. Seven hydrogeologic areas were established. The hydrogeological characteristics of each area were described and related to the pedological characteristics of the soils. In addition, a detailed sampling of the soil and sub-soil was conducted to evaluate the degree and source of salinity in the soil. The pedologic, hydrogeologic, and geochemical data indicate that the general soil salinity pattern is controlled by a complex configuration of the groundwater flow system. Saline soils occur in areas of dominant groundwater discharge. Leached soils occur in areas of dominant groundwater recharge. On a micro-scale local groundwater flow systems and the vertical and lateral distribution of salinity are governed by micro-relief and micro-stratigraphy of the surface deposits. In some areas thin sand and gravel lenses above and slightly below the water table strongly influence the distribution of soluble salts in the soil. The major source of soluble salts in the region was attributed to the dissolution of sulphate minerals in the glacial till.