Comparison of Three Groundwater Models with Finite Element Methods for Groundwater Head Simulation

Abstract

The goal of the study was to contrast three groundwater models that use the finite element approach to simulate groundwater head prediction, SUTRA, FEMWATER, and FEFLOW. With an area of 60 km², the research area is the micro watershed in the Cheyyar River basin. The primary lithological unit in the studied area is charnockite, which is accompanied by the Gneiss complex in the foothill region. The aquifer systems are made out of weathered rock and cracks. The surface water accessible has eight large water basins and little canals for drainage. The majority of the study area is covered by agriculture, with certain areas of the western, northern, and southern regions having some forest cover. For irrigation, groundwater is utilised. The research area's border conditions, aquifer thickness and lateral extents, aquifer hydrogeological features, drainage and water bodies, elevation, the position of wells, and other topographical and hydrogeological data are all included. Operational data, such as pumping and recharging rates, and meteorological data, such as local precipitation, runoff, and water balance. The model’s input is prepared and given the beginning condition, such as the groundwater level relative to mean sea level. The research area is transformed into a conceptual model, where the required volume of space is established, including the lateral and vertical expansion of modelling volume. The finite element solution method is used to solve the space volume formed by the mesh. Three models—SUTRA, FEMWATER, and FEFLOW—perform the finite element solution. The monthly time step simulated groundwater heads for the years 2021 and 2022. Groundwater level measurements are used to validate the model once it has been calibrated for the hydrogeological parameters. With R² values of 0.72, 0.78, and 0.8 for the SUTRA, FEMWATER, and FEFLOW models, all three models perform well when computing the groundwater heads contours. The validation demonstrates that FEFLOW works best with simulations of groundwater heads.