Studies on groundwater resources using visual MODFLOW – A case study of Kadalundi river basin, Malappuram, Kerala

Abstract

Groundwater models describe the ground water flow and transport processes using mathematical equations based on certain assumptions. Visual MODFLOW is a complete and user-friendly, modelling environment for three dimensional ground water flow and contaminant transport simulation. In this study, Visual MODFLOW software version 2.8.1 developed by Waterloo Hydrogeologic Inc. was used for the flow modelling of Kadalundi river basin, which covers major geographical area of Malappuram district. This river basin can be considered as a general representation of the district. Base map was prepared using Arc GIS (Arc Map10.1) and imported into the model. The conceptual model for the study area was developed using the toposheet of the area, well logs at 30 sites and the data obtained from the geophysical studies conducted in the study area. The model was developed and calibrated with four years data (2008 to 2011) and validated with two years data (2012 and 2013). The validated model was used to predict the flow head for the next 15 years assuming 5% decrease in recharge for every year and also to predict the ground water condition by increasing the pumping rate by 10, 25 and 50% of pumping rate of the validation period (2013). From the modelling studies, it could be noted that the Kadalundi river basin may remain safe for a short span of five years from the point of future ground water development and subsequently the water table will reach the bed rock. This necessitates artificial ground water recharge techniques in the study area to supplement the ground water recharge through rainfall.