Development of an integrated numerical flow model in the Prairie Environment – A case study of the Leech Lake Aquifer system, Saskatchewan, Canada

Abstract

Study regionLeech Lake Aquifer, City of Yorkton, Saskatchewan, Canadian Prairies. Study focusGroundwater and surface water interactions have been conducted numerically for bringing out a sustainable management of the Leech Lake aquifer in the southern portion of City of Yorkton area within the province of Saskatchewan, Canada. The aquifer is composed of highly conductive sediments over bedrock strata with low hydraulic conductivity. A fully coupled, physically based surface-groundwater flow model using HydroGeoSphere (HGS) is developed for the purpose of simulation. In this numerical model, different withdrawal scenarios and the effects of climate variabilities (precipitation and snowmelt) are being conducted to investigate the impact of water usage on groundwater level. New hydrological insights for the regionGroundwater from several aquifers serves as the main water supply for the city of Yorkton. Aquifer protection and sustainable use of the limited resource is of utmost importance to the municipality and in support of economic development in the region. Insight and understanding of the risks and impact to the municipal groundwater supply is required. To address the sustainability of the aquifers in the area, a numerical model was developed to provide greater comprehension of the surface and groundwater fluxes. Model calibration and validation was completed with existing long term monitoring information from piezometers in the area. In the semi-arid environment of the Prairie Provinces, water withdrawal and precipitation plays a significant role in affecting groundwater level. Different withdrawal scenarios are conducted to investigate the impact of the water usage on the Leech Lake aquifer that will provide a tool to support the development of a sustainable management plan. Precipitation as well as snowmelt have been incorporated into the model to identify the driving recharge factor for groundwater variation. Temporal and spatial variabilities, as well as estimation of magnitude for exchange flow rates at the interfaces are presented. The fully integrated model developed in this study provides the foundation for future groundwater management applications in climate driven changes within the Prairie environment.