Evaluating groundwater depletion under natural and induced stresses: a numerical modeling approach toward aquifer sustainability

ABSTRACT The ever-increasing demand for freshwater has led to the overexploitation of aquifers. Despite its known importance, integrated studies reckoning the impact of external stress on budget components are limited. This study assessed the spatiotemporal impact of recharge and abstraction stresses in Lower Betwa River Basin (LBRB) aquifers, India, from 2003 to 2020, using SWAT and MODFLOW-NWT models. The simulated difference in groundwater inflow and outflow components was accounted by a net cumulative storage loss of 36.5 Mm3/year. Mann-Kendall trend analysis indicated that about 62 % of the LBRB showed a declining trend in groundwater levels (0 - 1.2 m/year), 30% of the area had no significant trend and around 8% area showed an increasing trend. Spatial storage variations indicated that 78% of basin area was under stable aquifer systems while 1.6% area was under very high storage stress. Application of management scenarios to reduce groundwater storage loss exhibited that a 20% reduction in abstraction rates would reduce storage loss by 29% and 16% in Bamaur and Gursarai blocks. An integrated approach of abstraction reduction and increased inflow through managed aquifer recharge was the most suitable management solution to offset groundwater depletion and achieve long term sustainability in the LBRB.