Hydrological feedbacks in groundwater dominated systems in northern India: approaches, challenges and projections of future change Ana Mijic, Imperial College London Land-use change and related changes in water use are key drivers of changes in the regional water cycle. This is especially the case for large-scale changes from bare and forested land into irrigated agriculture. Over the last decades, the Gangetic plains in northern India have undergone the world’s largest and fasted increase in irrigated agriculture. It is well known that groundwater extraction for irrigation is extensively decreasing the region’s water table levels, thus putting potential pressure on local water resources. However, determining the risks of water scarcity at a local scale, and predicting future trends requires a much more detailed assessment of local water fluxes. Land use change is affecting the partitioning of water fluxes, thus driving changes in recharge and runoff. These changes will affect surface and groundwater resources, while changes in evapotranspiration and soil moisture may feed back to atmospheric processes. Given the interactions between different hydrometeorological processes, a systems approach is needed. This talk will present a modeling setup that implements an integrated systems approach to simulating the hydrometeorological cycle of the Ganges basin, which is needed to resolve local and regional feedbacks to the water cycle that determine water resources and risks. Both the technical and scientific challenges to integrate modeling components dealing with groundwater, surface water, atmospheric and irrigation processes will be discussed. Some of the major challenges include the assimilation of heterogeneous data, model component evaluation and improvement, and uncertainty quantification. The project is part of a concerted effort to improve our understanding about historic and future changing water cycle, coordinated by the eponymous UK research council funding initiative. The projects funded under this programme jointly explore the complex interactions between various components in the hydrological cycle and changes as a consequence of climate and land use drivers.