Western Kansas is one of the most important agricultural regions in the world. Most agricultural production in this semi-arid region depends on the consumption of nonrenewable groundwater from the High Plains Aquifer, which will be 70 % depleted by 2070. The problem of depletion has drawn significant attention from local citizens and policymakers at the federal, state, and local levels for at least 40 years, resulting in a variety of policies and institutions to manage groundwater from the aquifer as a common pool resource. Yet depletion has persisted. We explain this conundrum as an outcome of a mismatch between the scale of resource management, which has become more intensively local, and the scale of resource exchange, which has rendered the High Plains Aquifer a global common pool resource. We then explain the deeper, structural origins of the management-exchange scale mismatch. Drawing on concepts from structural human ecology theory and empirical evidence from Southwest Kansas, we show that agriculture is predicated on local metabolic rift in the hydrological cycle that is exacerbated through ecological unequal exchange with higher-income, core areas beyond the region. We conclude by highlighting two key policies that, if implemented together, may lessen the deleterious effects of these structural dynamics and thus promote a more sustainable relationship between society and environment in this region and other water-scarce regions that are net-exporters of groundwater.