Modeling the impact of rainfall variations and management interventions on the groundwater regime of a hard-rock terrain in central India

Realistic assessment and prediction of groundwater resources, at appropriate scales, are crucial for proper management and systematic development of groundwater in India. An equivalent porous medium (EPM)-based groundwater flow model is implemented for a typical hard-rock aquifer in central India, to provide quantification, analysis and prediction of groundwater balance components. This research also provides refined estimates of aquifer parameters, recharge factors and newer insights into groundwater dynamics. It is observed that evaporative losses and effluent seepage of groundwater to rivers jointly account for 20% of the annual recharge, which is significantly higher than most prior regional assessments. Evaluation of groundwater resource use under a business-as-usual scenario shows annual groundwater draft to exceed recharge by 13% in the year 2020-2021, and under a worst-case scenario (with prevailing drought conditions) this deficit is predicted to increase to 30%. However, with suitable recharge augmentation and demand control measures, in the best-case scenario, groundwater draft can be contained to 90% of annual recharge, thereby ensuring long-term sustainability of groundwater resources. Importantly, this study reveals that demand control measures can be more effective than recharge augmentation measures.