3D-Mathematical model to simulate groundwater flow and sulfate concentration in Tantaria watershed, Bemetara district, Chhattisgarh, India

Groundwater is a precious natural resource. In this densely populated country, most of the areas are facing groundwater scarcity. Now, it is very challenging and also important to evaluate the aquifer and set mitigation, management strategy to provide a safe drinking water demand in this present Holocene time. Tantaria watershed of Bemetara district has been considered as study area because of its down going trend of water table and increasing trend of SO4 concentration in groundwater. To manage and set mitigation strategy for this problem, numerical groundwater modeling software GMS has been used. Water level and water sample have been collected from six different places of the study area and water sample have been tested in laboratory; the concentration of SO4 in three wells (Well No. 2, 3 and 4) are more than the acceptable limit. Hydrological data, empirical values and equations are used for the development of the groundwater transient flow-transport model, water budget estimation and to know the impact of over pumping by the help of MODFLOW & MT3D. The developed model is calibrated by matching computed and observed data with a fair level of accuracy. The study shows that the area is under threat with present rate of water extraction i.e., depletion of water table and rise of SO4 concentration. If this condition will proceed then water table of this area will deplete 2–2.5 m till 2022. So to mitigate this future out coming there is a need to reduce the pumping rate 20% than the present time which is deduced from the study.