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Additional Case Study Simulations of Dry Well Drainage in the Tucson BasinExecutive Summary: Three case study simulations of dry well drainage were performed using the saturated-unsaturated groundwater flow model UNSAT 2. Each case simulated injection of storm water runoff water into a dry well from two five-year, one-hour storm events, separated by a 24-hour lag period. The first case assumed subsurface conditions of a uniform gravelly sand material from land surface to the water table at 100 feet below land surface. The second case assumed the same gravelly sand, underlain by a uniform sandy-clay loam material beginning at 30 feet below land surface and extending to the water table. The third case assumed the same conditions as in Case 2, except for a sandy loam soil replacing the sandy-clay loam material. Simulated subsurface flow of injection water for the first case was primarily vertical. The cross-sectional radius of the 95% saturated portion of the drainage plume reached a maximum of about nine feet during stormwater injection. In the second and third cases, horizontal flow took place at the layer boundary between the gravelly sand and underlying fine material. As a result, the cross-sectional radius of the 95% saturated portion of the drainage plume reached a maximum of about 27 feet for Case 2, and about 21.5 feet for Case 3. Arrival times of injection water at the water table varied from between 0.25 and 0.75 hours (Case 1), and between 130 and 150 hours (Case 2). Attenuation of water-borne pollutants in the vadose zone is related to the degree of exposure of drainage water to soil particle surfaces. The specific surface area of soil particles to which drainage water was exposed was used as an indicator of the relative degree of attenuation that may take place among the three cases. The ratio of specific surface area of soil matrix exposed to the portion of the subsurface reaching a state of 80% saturation was approximately 1 : 16.2 : 5.6 (Case 1 : Case 2 : Case 3).
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Alternative Uses of Treated Wastewater in ArizonaIntroduction: In the wake of renewed concern in recent years about environmental quality and its preservation, much has been said about the apparent conflict between environmental quality and economic development. In many instances these two objectives would seem to be in direct opposition to one another; in fact, as indicated by Cleary (1972), pollution in times past was accepted as the inevitable penalty of progress, as measured by economic growth. Currently, however, a popular view is that pollution is not socially acceptable and must be eliminated (the "zero-discharge" concept), almost without regard to economic considerations. While we are attempting to achieve a state of balance between these two approaches, it is evident that some activities can be so directed as to serve both objectives -- pollution control and the economic utilization of a resource. An example is the allocation of treated municipal wastewaters to beneficial uses, such that their environmental pollution potential is decreased, while they simultaneously serve as an input to an economically productive process or water-use activity.
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Applications of the Compartmented Reservoir in Arizona: Project Completion ReportThis report contains the results of a one year study to apply the compartmented reservoir concept to water storage problems in Arizona. The range of selected projects was from a ten thousand cubic meter (8.1 af) reservoir for a water harvesting agrisystem at Black Mesa, to a 238 million cubic meter (200,000 af) flood control dam, Tat Momolikot Dam on the Papago Reservation, to supply water for irrigation. Other sites studied were the Santa Cruz River at Continental, to supply an industrial /domestic water, Leslie Creek site for recreation, and improvement of Mormon Lake for recreation. Evaporation from Tat Momolikot and Mormon Lake are presently consuming most of the available water. Through compartmentalization this evaporation can be significantly reduced. At the other potential dam sites on the Santa Cruz and Leslie Creek the use of a compartmented reservoir will make these otherwise marginal projects practical. The Black Mesa Agrisystem is presently demonstrating the utility of the compartmented reservoir system.
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Arizona's Ground-Water Resources and Their ConservationAs Arizona enters the 1980's, we see that population growth, economic expansion, and resource depletion go hand-in-hand. Non-renewable groundwater-reserves in Arizona are being extracted at rates that cannot long continue without incurring serious consequences, economic as well as environmental. Growth of irrigated agriculture in the alluvial basins of the state, growth of urban and suburban populations, and,growth of industrial pumping, especially for copper mining -milling and for cooling of electric power generation facilities, have incurred a heavy draft on the state's aquifers. The net result of such ground-water withdrawals has been the "mining" of underground water reserves, a continuing overdraft in excess of natural replenishment, and steadily dropping water tables. This rate of depletion of ground water is generally considered to be the most serious water problem in Arizona. It is by no means the only problem. We must be concerned also with maintenance of water quality in view of existing and potential pollution; administrative systems for equitable and efficient water allocation and use; and the legal and environmental aspects of water acquisition and utilization.In order to assess present and possible future water conditions in the state relative to growth, water resources will be viewed from the standpoint of (1) water usage, both quantitative and qualitative; (2) conservation of water; (3) availability of water; and (4) projected water needs.
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Arizona's Solar Powered Community: Sizing and Cost Estimate of a 24-Home PrototypeIntroduction: On January 12, 1987, Governor Mecham stated that he intended to build a solar powered community. A solar powered community would produce as much power from the sun as it would consume. Thus, it would be self sustaining as far as energy is concerned. One of the most cost-effective ways of powering a community appears to be the combination of using a hybrid thermal/photovoltaic collector. with seasonal storage of water in an insulated pit providing thermal energy to the homes in the community using district heating and cooling. In order to demonstrate the cost effectiveness of this system in the desert areas of southern Arizona, a project was designed and a cost was estimated for a 24-home subdivision in the Phoenix area.
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Asphalt-Crumb Rubber Waterproofing MembraneThis report is concerned with laboratory testing and field investigations of a water seepage barrier consisting of asphalt cement and reclaimed crumb-rubber tire peel. The test methods that were utilized and evaluated included the following: water vapor transmission (ASTM E96 -72, Procedure BW), water absorption (ASTM 570-72), ductility (ASTM D113-74), viscosity, toughness, and brittleness /impact resistance (ASTM 0994-72). The test results showed that the asphalt-rubber as a membrane is relatively impermeable and absorbs an insignificant amount of water. The crumb rubber effectively increases the viscosity of the asphalt cement while decreasing the ductility value. The asphalt-rubber combination exhibits a tough, impact resistant membrane with excellent waterproofing properties.
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Bibliography on Ground-Water Recharge in Arid and Semiarid Areas: Project Completion ReportThis bibliography provides references on natural and man-caused recharge in arid and semiarid areas. The literature on natural recharge includes citations on stream channel recharge, mountain recharge, mountain -front recharge and precipitation-infiltration recharge. The literature on man-caused recharge includes citations on recharge from activities such as irrigation, mining and waste-water treatment and disposal, but does not include citations on artificial recharge. Most citations are abstracted; all are keyworded. The bibliography may be accessed through keyword and author indices.
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Brackish Water as a Factor in Development of the Safford Valley, Arizona, U.S.A.Introduction: The Safford Valley area lies along the Gila River in the southeastern part of the State of Arizona. The portion of the valley being considered, see Figure 1, is an intermontane trough averaging about 15 miles (24.2 kilometers) in width and about 30 miles (48.3 kilometers) in length. The cultivated lands lie along the Gila River and are 0.5 to 3.5 miles (0.8 to 5.6 kilometers) from the river. The approximately 14,000 inhabitants of the valley are primarily located in the municipalities, and Safford, the largest of the towns, was founded in 1875. Agriculture and agriculture-dependent activities, however, provide the mainstay of the Safford Valley economy accounting for approximately 63 percent of the export employment (State of Arizona, 1971). Like many valleys in arid regions, the Safford Valley, because of an inadequate supply of good quality water, has been forced to depend on ground water of notoriously poor quality. The purpose of this paper is to show how the limitation of available good quality water and the need to use brackish water affects agricultural practices and industrial development in the Safford Valley.