Urban Metabolism and the Energy-Water Nexus in Phoenix, Arizona

azhydrosoc.org

The nexus between power and water is undeniable. In semi-arid and arid regions, the generation of power holds much controversy because of its dependence on water. In 2000, thermoelectric generators in Arizona consumed 113,000 acre-feet per year of fresh water and this number will surely rise as Arizona's population increases. With such large volumes of water, the trade off between water for consumption and water for power becomes a contentious issue. In Arizona, scarce water resources, an increased demand for power due to rapid population growth, and the politics behind Central Arizona Project (CAP) allocations compound this trade off. Simply put, CAP water allocated to an electricity generator cannot be used for human consumption and as the population rapidly increases this trade-off-water for power or water for human consumption-becomes more stressed.

Climate change, rapid urbanization, and the emerging carbon economy , among other factors, have elevated the energy-water nexus from an operational tool to a new joint-resource management and policy paradigm. Nowhere in North America, and in few regions globally, is this need greater than in the Southwest United States and Northwest Mexico. In the states of Arizona and Sonora, investment is inadequate to meet energy and water infrastructure needs. On par with critical infrastructure in economic development terms, agriculture is likewise energy-intensive and currently consumes the largest share of water resources in both states. The important gains for their dedicated interest in the water-energy nexus in Arizona. Both made many of the calculations of water used in electrical generation and energy used in the urban water cycle. Mr. Hoover and Lily House-Peters helped prepare the bar graphs. Mr. Kelley prepared the maps. Special thanks are extended to Katharine Jacobs, Placido dos Santos, Robert Varady, Gregg Garfin, Subhrajit Guhathakurta, and numerous individuals and agencies that provided us with data and reports. 645 646 NATURAL RESOURCES JOURNAL [Vol. 50 to be made through coupled energy-and water-based conservation, including the potential of certain types of renewable energy development to reduce water requirements for electricity generation, raise questions over conventional plans to rapidly increase investments in infrastructure. The purpose of this paper is to assess the region's energy-water nexus through analysis of data on water supply, electrical power generation, and energy consumption. Four cases are examined to illustrate the coupled nature of policies for energy and water: (1) rapidly growing urban centers; (2) water consumed in power generation and the " virtual water " implications of regional interstate power trade; (3) the irrigation-electrical power nexus in agriculture; and (4) coastal desalination and proposed trans-boundary transfer schemes. The paper concludes that conventional water management for cities has a large and rising energy footprint. Conversely, power generation that is often considered " non-con-sumptive " in this arid region is a major consumer of water. Similarly , there is a major opportunity for energy and water conservation in groundwater irrigation. Finally, desalination may hold promise, particularly for coastal communities, but current costs and institutional barriers suggest that transboundary transfer of desalinated water for general purposes, including environmental conservation and agriculture, has low feasibility.

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the effect of hydroclimate variability on economic growth

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Figure to be inserted I n t e r n a t i o n a l Water Management I n s t i t u t e The Comprehensive Assessment of Water Management in Agriculture takes stock of the costs, benefits and impacts of the past 50 years of water development for agriculture, the water management challenges communities are facing today, and solutions people have developed. The results of the Assessment will enable farming communities, governments and donors to make better-quality investment and management decisions to meet food and environmental security objectives in the near future and over the next 25 years. The Research Report Series captures results of collaborative research conducted under the Assessment. It also includes reports contributed by individual scientists and organizations that significantly advance knowledge on key Assessment questions. Each report undergoes a rigorous peer-review process. The research presented in the series feeds into the Assessment's primary output-a "State of the World" report and set of options backed by hundreds of leading water and development professionals and water users. Reports in this series may be copied freely and cited with due acknowledgement. Electronic copies of reports can be downloaded from the Assessment website (www.iwmi.org/assessment). If you are interested in submitting a report for inclusion in the series, please see the submission guidelines available on the Assessment website or send a written request to: Sepali Goonaratne,

2018

Water consumption is a problem, as it is used inefficiently, besides that, the demand is growing much faster than nature can supply, so in the present study an analysis was conducted to determine the amounts of water used in domestic and agricultural activities in a rural town, that allows us to obtain the water shortage index. To define and know the different uses, a survey of people's perception of household water expenditure is used, both personal hygiene and at home, as well as the use in agricultural activities. Then, the water shortage index is calculated with the model IDEAM (Hydrology, Meteorology and Environmental Studies Institute) modified by Romero and Ortiz (2016), which was adapted to a rural area. The agricultural and domestic activities need 868, 500, 660 L/ha, equivalent to 72.8 % of the total water rains in the study area and, the amount that is not used is 344,982,477 L/ha, what represents the 27.2 % of the total 100 %, the latter is for the recharges of wells...

The universe is constituted of five basic elements: Earth, Water, Fire, Air and Light according to Rig-Veda, all life evolved from water. Unique properties of water make it essential for life 1 . More than two third of the earth's surface is covered with water 2-3 . The amount of water present on earth is estimated at about 1.41 billion km 3 of which only about 2.5% is fresh water. The overwhelming part the other 97.5% is sea or brackish water unsuitable for human use. The greatest part of the fresh water 87% is contained in ice caps or glaciers if the total amount of the earth's water were 100 liter then the amount of usable fresh water would be only 0.003 liter or half a teaspoon 4-7 .