HGS RESEARCH HIGHLIGHT – Development of an integrated numerical flow model in the Prairie Environment

AUTHORS: Arefin Haque, Amgad Salama, Kei Lo, Peng Wu

A recent publication by researchers at the University of Regina uses HydroGeoSphere to investigate the impact of climate variability and different groundwater withdrawal scenarios on groundwater levels in the Leech Lake aquifer. This paper provides an excellent introduction to the use of HGS in semi-arid prairie regions, making use of the built-in evapotransporation and snowmelt processes to estimate overall recharge rates under various climate scenarios (including extreme drought).

“The interaction between surface water and groundwater is complicated due to the existence of many factors, such as uncertainty of land cover and aquifer properties, which can cause substantial errors in model output (Eslamian and Nekoueineghad, 2009; Sophocleous, 2010; Straatsma et al., 2013). A fully-integrated, physically-based numerical model is well capable of handling these factors (Alaghmand et al., 2014). HydroGeoSphere (HGS), fully integrated model has been selected for this research because of its capability to address some of these complexities while considering a large scale study (Therrien, 2011). HydroGeoSphere can simulate the dynamic interactions between all sub-domains at each time step.”

“In HGS, rainfall precipitation is branched into components such as evapotranspiration, runoff and infiltration. HGS allows for the computation of water infiltration or exfiltration between rivers, lakes and aquifers. These interactions play a significant role in the prediction of future scenarios with respect to climate change, since recharge (precipitation, snowmelt) is very susceptible to climatic fluctuations.”

This study was co-authored by researchers at the University of Regina (Faculty of Engineering and Applied Science) and the Saskatchewan Water Security Agency. For more information, please contact the corresponding author Peng Wu (Assistant Professor and Program Chair, Environmental Systems Engineering; Peng.Wu@uregina.ca). 

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Abstract:

Study focus: Groundwater 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 region: Groundwater 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.