The level of Lake Mead is often used as a proxy for water availability in the basin

A constraint in one system could not only affect economic security in that system but could inhibit access in another. Therefore, the nexus provides a powerful means to improve synergies in food, energy, and water production , to identify how stressing food, energy and/or water systems creates resource vulnerabilities and/or resource scarcities in all three, to understand and quantify the production of ecosystem services, and to develop climate adaptation strategies. However, historically, food, energy, and water systems have been pigeonholed politically as well as broken up into small disjointed pieces that cross political boundaries and do not align with bio-regions or watersheds. This type of disjointed management leaves policy makers ill-equipped to provide resilient management strategies. Thus, the success of using the nexus concept to improve food, energy, and water systems will likely depend on how it incorporates issues surrounding resource governance , including how governance and the discourse of securitization become a way to legitimize political agendas. Many have argued that the nexus discourse of security places economic variables over access to resources for the world’s poor, an idea that can be traced back to Foucault’s theory of the linkages between security and the circulation of the global economy. In addition to this discursive ‘securitization’, resource governance outcomes are based on the larger political goals of the government or states involved in policy making. The connections between discourse, policy,diametro maceta 10 litros and land management, therefore, raise important questions regarding how policy is already impacting nexus outcomes and communities on the ground.

Given the recent emergence of the FEW concept, few studies to date have explored the use of the nexus concept simultaneously with an analysis of governance structures. To address this gap, we present a quantitative application of the FEW nexus concept to study resource vulnerabilities and scarcities in the Lower Colorado River Basin in California, Arizona, and Nevada, U.S.A. We analyze the nexus within its sociopolitical, economic, and bio-regional context that determine what resources are available, used, produced, and traded. We take a case study approach, as case studies are best able to translate the on-the-ground nexus realities of a variety of institutions, bureaucracies, and stakeholders across space, time, and scale. Our goal was to understand how the governance structure of the Colorado River constrains the utility of the nexus approach to deal with future stresses. To do this, we first quantified the nexus by identifying the local and global linkages between food, energy, and water as well as the choices confronting water managers, and the Indian Reservations in the study area. We use these findings to look for the emergence of tipping points under two different scenarios: drought and increased demand for alfalfa. We then discuss how the very rigid water laws in the LCRB constrain the ability to improve resource management and respond to these tipping points using nexus thinking. While the main focus of this paper is on how economic and hydraulic factors influence FEW’s nexus governance, in the discussion we also examine the impact of institutional and political factors as well as geopolitics across the transnational boundary between the U.S. and Mexico.The Colorado River Basin has a semiarid to arid climate with an average of 40 cm annual precipitation that originates as snow pack in the Rocky Mountains and contributes to about 70% of the total stream flow in the basin. However, temperatures have been rising for the past century, with winter temperatures increasing more than summer temperatures on average by 2 °C. 

Temperatures are predicted to rise at least another 1.1 to 2.0 °C by 2050. These higher temperatures increase evaporation rates and have coincided with a reduction in snow pack and snow melt in the UCRB. In addition, the LCRB has been in a drought since 2002, though at the same time the UCRB has experienced less severe or no drought conditions, outside of extremely dry periods in 2003 to 2004, and 2012. Historically, paleo climatic records indicate pervasive and long-lasting periods of drought occur in the region. However, more recently, the area has received significantly more snowfall.Its water elevation has been decreasing since 2000, which can be seen visually in aerial imagery.The Colorado River is operated under the “Law of the River,” which is comprised of a variety of U.S. federal laws, agreements, court decisions, and regulatory guidelines. These laws apply to seven Western U.S. states: Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming, and Mexico that utilize water from the river. The Law of the River allocates to each basin 7.5 million acre-feet 1 of water per year in perpetuity, with some exceptions that account for water scarcity. High variability in precipitation in the Rocky Mountains results in 5 MAF to 25 MAF of flow in any given year with an average annual flow of less than 16.4 MAF/yr. In terms of usage, on average 91.4% of the allocated water is used by municipalities, for power, or agriculture. The UCRB Indian reservations receive 1 MAF a year, while the LCRB Native American reservations are allotted 0.9 MAF a year. While this water is split amongst the 20 reservations in the LCRB, only six reservations have had their water rights quantified. This has resulted in a disproportional amount of water allotted per person on these reservations compared with the rest of the basin. Specifically, 6.7 AC-FT per person per year is allotted to Lower Basin Indian reservations while 0.9 AC-FT per person per year is allotted to the rest of the LCRB. It should be noted that the water allotments of both basins , Mexico ,macetas cultivo and the Native American Reservations , adds up to 18.4 MAF, 2 MAF more than the yearly average stream flow of the Colorado River not accounting for climatic fluctuations.

The rigid allotments based on the Law of the River have also resulted in most of the agriculture production in the study area taking place on Indian reservations. Prior to the Law of the River, American Indians practiced flood farming practices for thousands of years based on characteristic seasonal rains , as well as dry farming. Today, however, practices are much more water-intensive on Indian Reservations.The Colorado river allows local economies to exist in a semi-arid environment with two-thirds of Arizona’s, California’s, and Nevada’s state gross products dependent on the Lower Colorado River. The river provides 657.5 billion dollars of direct, indirect, and induced GDP to California; 185 billion dollars to Arizona; and 115.4 billion dollars to Nevada. Focusing on food systems, agricultural production in the study area is largely situated on Indian reservations due to their high allotment of river water.For alfalfa, one of the most common crops in the region, the water that is used to flood the fields is sent back into the canals. The high-water availability along with the warm climate allows the production of twelve harvests of alfalfa each year. Most of the alfalfa is exported as fodder to China, followed by Japan, Mexico, South Korea, and the EU.A diversity of data sources drawn from the Food and Agriculture Organization of the United Nations , the United States Department of Agriculture , and the Energy Information Association were used to quantify the connections between food, energy and water.Energy was quantified in terms of net generation and cost for hydroelectric, natural gas, solar, and wind generated in the region for 2001 to 2016. Food production was quantified in terms of area of agricultural crops as well as the price that farmers spent on production for 2008 to 2015. Only crops that took up greater than 1% of total area were analyzed. To determine the total impact of one sector on another , we combined the total amount of water used in energy or food, and the total amount of energy used to pump water or produce food.Water-energy linkages were quantified in two different ways. First, the amount of water used in energy production 2001 to 2016 was calculated by multiplying the appropriate water consumption factors of electricity generated from natural gas from Spang et al., 2014 by the amount of energy produced monthly from 2001 to 2016. Water used in natural gas extraction for gas used in the study area was not included since there are no natural gas extraction operations within the basin. Hydroelectric projects have no net water consumption, but reservoirs make evaporation rates higher, especially with higher temperatures. Second, energy used to transport water in the Colorado River Aqueduct was quantified using data obtained from the Metropolitan Water District of Southern California for 2001 to 2016.

The aqueduct conveys water from Lake Havasu over the Santa Ana Mountains and to cities in Southern California, including Los Angeles. In addition, energy used to transport water from Lake Havasu to Phoenix and Tucson via the Central Arizona Project was drawn from a previous study by Kleiman. A final water-energy linkage, the amount of energy need to purify wastewater for domestic consumption was not quantified due to lack of data. Generally, however, wastewater treatment accounts for ∼3% of energy used in the United States.First, information on specific crop water usage was estimated using evapotranspiration rates in ft/growing period and average area cultivated annually for six of the seven most common monocrops in the LCRB. All data came from FAO estimates except for lettuce. FAO evapotranspiration estimates are given in mm/growing period, however, we converted the units to ft/growing period so we could easily translate the measurement to volume of water in AC-FT. Second, data for 2007, 2012, and 2013 from the National Agricultural Statistics Service for the entire Lower Colorado River Basin was used to estimate yearly water used for irrigation. In order to calculate the data at the watershed subunit level, we used the United States Agriculture Service 2012 Census and Cropland Data Layer to estimate the percent of irrigated land out of the total acres of cropland. The proportion of cropland that was irrigated varied based on data year, in 2013, 67.74% of cropland was irrigated; in 2012, 75.82% of cropland was irrigated; and in 2007, 71.21% cropland was irrigated. We averaged the percent of cropland irrigated in the watershed subunit for 2007, 2012, 2013 to extrapolate to the remaining years from 2008 to 2015. The average irrigation estimate was used in the production scenarios to understand responsiveness of irrigation and crop production to changes in climate.The linkage between food and energy was quantified in two ways. First, we estimated the amount of direct usage of fossil fuels by calculating the amount of fuel farmers purchased to run farm machinery in 2012. Second, using the 2013 NASS estimation for energy expended in irrigation for the entire LCRB, estimated at $49.00 per acre, we estimated the cost for irrigation in the study area. Using the cost per amount of energy we converted $49.00 per acre to the amount of energy in MWH used for irrigation in the study area. Assuming that the price of energy needed to irrigate remained constant, we calculated the energy expense for all years using the estimated irrigated cropland and cost per amount of energy for those years.As expected for a temperate semi-arid climate, the amount of water consumed followed a seasonal pattern with increased use during the summer months and decreased use during winter. Across Arizona, California, and Nevada, the main consumptive water use was either irrigation or municipal use, depending on the year. In 2013, the biggest consumers in Arizona and California were large cities such as Phoenix, Tucson, and irrigation districts. Water to cities in Arizona was transferred through the Central Arizona Project with over 1.5 MAF consumed. The Imperial Irrigation District was California’s largest water consumer in 2013, consuming more than 2.5 MAF of water. The Metropolitan Water District that transfers water to Los Angeles consumed less than the Central Arizona Project with just over one MAF. In Nevada, there are no consumptive uses over 100,000ACFT. However, the City of Las Vegas receives its water right before it reaches Lake Mead, so this is not accounted for in our analysis.