Human mediated physical and virtual water transfers of the United States: Who uses the water?

Globalization has strengthened and expanded connections between consumers and distant water resources used in production, by enabling consumer demand in one location to be fulfilled with production and resource use in another. Many of the environmental consequences associated with water-intensive production, particularly agricultural production, are not felt by those consuming the products but are left as an artifact for producing communities. Consumers increasing dependency and influence on nonlocal water use decisions can lead to water scarcity, groundwater depletion, or other environmental impacts, but, with better understanding, can provide an opportunity for innovative and sustainable solutions to local water issues. The primary goal of this dissertation is to better understand the telecouplings between nonlocal consumers, which drive transfers of water and water-intensive goods, and the overexploitation of local water resources. There is an incongruity between the scale at which water is studied and managed and the scale that water dependencies and impacts coalesce; this dissertation begins to resolve this mismatch of scale. This work provides an important first step toward empowering producers, consumers, water planners, and decision makers to manage water resources more holistically and at the appropriate scale by linking understanding of local production water consumption with new knowledge of virtual water transfers - that is, the water embedded in the production of traded commodities. We draw upon publicly available data on agricultural production, water withdrawals and consumption, water infrastructure, and trade, as well as modeled estimates of agricultural water requirements to quantify virtual water transfers between producers and consumers. A novel dimension of this research is the fine spatial, temporal, commodity, and water source resolution made possible through empirically-based datasets and our unique methodological approach. In this dissertation, we quantify and track agricultural virtual groundwater transfers from the overexploited Mississippi Embayment, High Plains, and Central Valley aquifer systems in the United States to their final destination. Specifically, we determine which US metropolitan areas, US states, and international export destinations are currently the largest consumers of these critical aquifers. Next, we study drought impacts to food and virtual water transfers from the Central Valley of California and examine the linkage between distant consumption of virtual water resources and local water impacts. More broadly, this study elucidates how local climate shocks reverberate through the global food system, highlighting the importance of complex interactions in the coupled climate-food-water system, and the critical role of local groundwater depletion. A comprehensive, high-resolution database was also created that estimates the water footprint of US production and the virtual water contents of food, energy, services, manufacturing, and mining products produced within the US. This work elucidates how different water sources within the US support the country's economy, explicitly relating these water sources to over 500 different industries and products. Finally, an interdisciplinary framework to mitigate the complex social and natural barriers to physical water transfers is put forth.Ope