Food consumption and production are separated in space through flows of food along complex supply chains. These food supply chains are critical to our food security, making it important to evaluate them. However, detailed spatial information on food flows within countries is rare. The goal of this paper is to estimate food flows between all county pairs within the United States. To do this, we develop the Food Flow Model, a data-driven methodology to estimate spatially explicit food flows. The Food Flow Model integrates machine learning, network properties, production and consumption statistics, mass balance constraints, and linear programming. Specifically, we downscale empirical information on food flows between 132 Freight Analysis Framework locations (17 292 potential links) to the 3142 counties and county-equivalents of the United States (9869 022 potential links). Subnational food flow estimates can be used in future work to improve our understanding of vulnerabilities within a national food supply chain, determine critical infrastructures, and enable spatially detailed footprint assessments.

The United States plays a key role in global food security by producing and exporting agricultural products. Groundwater irrigation is increasingly important in agricultural production, nearly tripling since records began in 1950. Increased reliance on groundwater and prolonged unsustainable pumping of aquifers has led to groundwater depletion in many areas. In this study, we ask: How much groundwater depletion is embedded in the domestic transfers and international agricultural exports of the United States? How much do domestic and international agricultural commodity fluxes rely on unsustainable groundwater use? To address these questions, we quantify the amount of nonrenewable groundwater that is incorporated into agricultural commodities produced in the United States and transferred both within the country and exported internationally. We find that 26.3 km 3 of nonrenewable groundwater was transferred domestically in 2002 and 2.7 km 3 was sent abroad. In 2012, 34.8 km 3 was transferred domestically and 3.7 km 3 was exported. This indicates an increase of 32% in domestic transfers and 38% in international exports. In 2002, we find that 1,491,126 kt (340 billion USD) of agricultural products reliant on nonrenewable groundwater were domestically transferred, while 119,048 kt (47 billion USD) were exported. In 2012, the mass transfer of agricultural goods reliant on unsustainable groundwater decreased, but their value in national and international supply chains increased by 54% and 31%, respectively. Our results underscore the importance of the long‐term risks posed to global agricultural supply chains from reliance on unsustainable groundwater use.

Disasters evolving from hazards are a persistent and deadly occurrence in the United States. Despite this, hazard alerts have remained spatially vague, temporally imprecise, and lack actionable information. These deficiencies indicate a divide between the status quo and what is possible given modern environmental models, geographic information systems (GIS), and smartphone capabilities. This work describes an alternative, prototype system, “FloodHippo,” which integrates operational model outputs, cloud‐based GIS, and expanded communication channels to provide personal and interactive disaster alerts for floods. The precepts and methods underpinning FloodHippo apply equally to other disasters that evolve over space and time, presenting the opportunity for a more intelligent disaster response system. The development of such a system would not only minimize current shortcomings in disaster alerts but also improve resilience through individual action, along with community, academic, and federal cooperation.

The United States is a major agricultural producer and breadbasket for the world, making it important to understand how specific crops use irrigation water supplies throughout the country and over time. Irrigation water use (IWU) is primarily composed of surface water sources and withdrawals of groundwater, including non-renewable withdrawals of groundwater (i.e., groundwater depletion [GWD]). Increased reliance on unsustainable water use in agriculture poses a potential future risk to the sustainable production of the global agricultural supply (Godfray et al., 2010;Siebert et al., 2015), making IWU particularly important to consider. In this study, we estimate crop-specific surface water withdrawals (SWW), (total) groundwater withdrawals (GWW), and GWD within the Continental United States (CONUS). Of note, we refer to total irrigation of all crops as "crop irrigation," and irrigation of particular crops (corn, wheat, etc.) as "crop-specific irrigation" for the remainder of this article. The main goal of this study is to better understand how irrigation water supplies (by source) are allocated amongst specific crops throughout the country, as well as any changes that have occurred with time. To achieve our goal, we create a novel database of IWU by crop and water source in the United States, which we make freely available with the paper.There are several agricultural growing regions in the US with different water demands. The "cornbelt" in the US Midwest is known for growing the majority of US corn and soybeans. Globally, the US is the largest producer of corn, producing ∼30% of global corn in 2019 (FAO, 2021). As of 2019 Brazil is the largest global producer of soybeans, but the US is a close second, producing ∼29% of soybeans globally in 2019 (FAO, 2021). Grain production in the US Midwest is primarily rainfed, although farm fields are increasingly equipped with irrigation as rainfall patterns shift with a changing climate. California is the "fruit and vegetable basket" for the country, with abundant production of predominantly nuts, seeds, and citrus crops, as well as all varieties of fruits and vegetables. California agriculture relies on conjunctive use of surface and groundwater irrigation. The USA as a country provides 55% of the world's almonds, 37% of pistachios, 13% of walnuts, 13% of lettuce/chicory, 11% of strawberries, 9% of sugar beets, 8% of grapes, and 6% of tomatoes (FAO, 2021).

Extensive research has evaluated virtual water trade, the water embodied in traded commodities. However, relatively little research has examined virtual water storage or the water embodied in stored commodities. Just as in physical hydrology, both flows and stocks of virtual water resources must be considered to obtain an accurate representation of the system. Here we address the following question: How much water can be virtually stored in grain storage in the United States? To address this question, we employ a data‐intensive approach, in which a variety of government databases on agricultural production and grain storage capacities are combined with modeled estimates of grain crop water use. We determine the virtual water storage capacity (VWSC) in grain silos, map the spatial distribution of VWSC, calculate contributions from irrigation and rainwater sources, and assess changes in VWSC over time. We find that 728 km3 of water could be stored as grain in the United States, with roughly 86% coming from precipitation. National VWSC capacities were 777 km3 in 2002, 681 km3 in 2007, and 728 km3 in 2012. This represents a 6% decline in VWSC over the full 10‐year period, mostly attributable to increased water productivity. VWSC represents 62% of U.S. dam storage and accounts for 75–97% of precipitation receipts to agricultural areas, depending on the year. This work enhances our understanding of the food‐water nexus, will enable virtual water trade models to incorporate temporal dynamics, and can be used to better understand the buffering capacity of infrastructure to climate shocks.

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The United States plays a key role in global food security by producing and exporting agricultural products. Groundwater irrigation is increasingly important in agricultural production, nearly tripling since records began in 1950. Increased reliance on groundwater and prolonged unsustainable pumping of aquifers has led to groundwater depletion in many areas. In this study, we ask: How much groundwater depletion is embedded in the domestic transfers and international agricultural exports of the United States? How much do domestic and international agricultural commodity fluxes rely on unsustainable groundwater use? To address these questions we quantify the amount of nonrenewable groundwater that is incorporated into agricultural commodities produced in the U.S. and transferred both within the country and exported internationally. We find that 26.3 km 3 of nonrenewable groundwater was transferred domestically in 2002 and 2.7 km 3 was sent abroad. In 1 2012, 34.8 km 3 was transferred domestically and 3.7 km 3 was exported. This indicates an increase of 32% in domestic transfers and 38% in international exports. In 2002, we find that 1,491,126 kilotonnes (340 billion $USD) of agricultural products reliant on nonrenewable groundwater were domestically transferred, while 119,048 kilotonnes (47 billion $USD) were exported. In 2012, the mass transfer of agricultural goods reliant on unsustainable groundwater decreased, but their value in national and international supply chains increased by 54% and 31%, respectively. Our results underscore the importance of the long-term risks posed to global agricultural supply chains from reliance on unsustainable groundwater use.

No abstract