India

India boasts the largest irrigated agricultural system in the world relying on groundwater. To address the strong linkages between the natural groundwater and the anthropogenic irrigated system requires innovative hydrological modeling geared at informing national policies on groundwater management and future development of irrigated agriculture. For this, we developed a predictive, integrated hydrological and groundwater use model and evaluated the model using total water storage (TWS) data from the Gravity Recovery and Climate Experiment (GRACE). The utility of the model was demonstrated in a case study in which the model was applied to project the groundwater balance in northwest India under four RCP (Representative Concentration Pathways) scenarios.

The model shows good identifiability to GRACE data in northwest India and with incorporated groundwater irrigation simulation module the model can adequately replicate the declining trend in TWS over this region. It is concluded that by assuming a unchanged pattern of agricultural water use climate change is likely to help reduce the magnitude of the groundwater deficit, but the beneficial effect is insufficient to halt the trend of groundwater depletion. This result provides new evidence for the importance of groundwater conservation through changes in cropping patterns and improved groundwater governance.