Changing groundwater storage trend of India after severe drought

Groundwater (GW) storage plays a critical role in the sustainable development of the water-energy-food nexus of a country. Intensive exploitation of GW for irrigation has led to severe water deficit in many parts of India. Severe droughts (meteorological drought) further increases the rate of GW depletion. In the last decade, India witnessed severe droughts during 2002, 2009, and 2012. However, the critical change in the rate of GW depletion in India after frequent severe droughts remains unidentified. Here, we have devised a methodology to detect the point of maximum fluctuation in Gravity Recovery and Climate Experiment (GRACE) based GW time series using change point analysis. The occurrence of 2009 severe drought has significantly affected the GW balance over the majority of India. Our study indicates the transition in the GW trend observed in South India from positive to negative post-2009 drought. In the southern states, Karnataka indicates a maximum GW depletion rate of 0.25 cm per month for a time period from 2009 to 2016.