RSS 1.0Hydrology and Water Resources in Arizona and the Southwest, Volume 21 (1991)
ABOUT THE COLLECTION
Proceedings of the Hydrology section of the Annual Meeting of the Arizona-Nevada Academy of Science. Full text manuscripts of work presented. Research related to water resources, water management, and hydrologic studies primarily focused regionally on southwestern US.
Volume 21. Proceedings of the 1991 Meetings of the Arizona Section American Water Resources Association and the Hydrology Section Arizona-Nevada Academy of Science.
April 20, 1991, Northern Arizona University, Flagstaff, Arizona
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Recent Submissions
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Hydrology and Water Resources in Arizona and the Southwest, Volume 21 (1991)Arizona-Nevada Academy of Science, 1991-04-20
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Arizona Reclaimed Water Regulation: The Future is NowLegal, legislative, technical and conservation factors have created a significant amount of reclaimed water reuse in Arizona. Critical recent events include: * Passage of the 1980 Groundwater Management Act * Arizona Department of Water Resources Management Plans * Passage of Environmental Quality Act * Creation of Arizona Department of Environmental Quality * 1989 Arizona Supreme Court Decision of the Status of Effluent * 1991 Arizona Reuse Rule Adoption Status
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Water Resource Management in the Lake Baikal RegionIn August 1990, a team of North American and Soviet researchers travelled to several cities on the shores of Lake Baikal in southern Siberia. The purpose of the investigation was to develop a means of protecting and restoring the world's oldest and largest volume lake. Lack of water resource management strategies was identified as the key factor which may result in further deterioration of lake water quality and the diversity of biota which it supports. Deforestation, antiquated agricultural practices, inadequate solid and liquid waste disposal, and industrial contamination threaten the aesthetic quality and commercial uses of the lake. The recommendations of the joint investigative committee are summarized.
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Assessing the Significance of Evapo-Sublimation in Northern ArizonaClimatic data for twenty-one winters was used to construct an index in order to assess the significance of evapo-sublimation at Flagstaff, Arizona. Large intra- and inter-annual variability was noted in the record using both uncorrected monthly index values and values corrected for the relative importance of snow. 1967-68 un- corrected sublimation opportunity index (SOI) values and similar values for both 1982-1983 and 1984-1986 appear to indicate that those winters either had unusually high snowpack evapo-sublimation losses, or were years of low "basin efficiencies". Evapo-sublimation opportunity might be tracked as a climate element for high elevational snowzones which contribute significantly to a regional water supply.
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The Effect of GIS Database Grid Size on Hydrologic Simulation ResultsThe use of geographic information systems (GIS) for assessing the hydrologic effects of management is increasing. In the near future most of our spatial or "mapped" information will come from GIS. The direct linkage of hydrologic simulation models to GIS should make the assessment process more efficient and powerful, allowing managers to quickly evaluate different landscape designs. This study investigates the effect the resolution of GIS databases have on hydrological simulation results from an urban watershed. The hydrologic model used in the study was the Soil Conservation Service Curve Number Model which computes the volume of runoff from rainfall events. A GIS database was created for High School Wash, a urban watershed in Tucson, Arizona. Fifteen rainfall-runoff events were used to test the simulation results. Five different grid sizes, ranging from 25x25 square feet to 300x300 square feet were evaluated. The results indicate that the higher the resolution the better the simulation results. The average ratio of simulated over observed runoff volumes ranged from 0.98 for the 25x25 square feet case to 0.43 for the 300x300 square feet case.
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Slowsand/Nanofiltration of Surface WaterSince the spring of 1988 the University of Arizona has conducted nanofiltration research. The major emphasis has been the treatment of both Colorado River Water and municipal effluent. The work has been sponsored by the John F. Long Foundation Inc. and the Consolidated Water Utilities, Phoenix Az. Nanofiltration is a low pressure form of reverse osmosis. It operates at about 1/3 the pressure and 3 times the flux rate of older brackish water reverse osmosis systems. This reduces both the cost as well as the operating costs to approximately 1 /10 of the older reverse osmosis systems. The City of Ft Myers is projecting costs as low as $0.50-0.60/1000 gallons for their 20 MGD plant. Nanofiltration treats water the way it needs to be treated to meet the Environmental Protection Agency's (EPA) present minimum contamination levels (MCL) as well as projected future levels. Nanofiltration removes most of the bivalent inorganic molecules such as calcium and magnesium as well as some monovalent molecules such as sodium and chloride. It also removes pathogens and dissolved organics, thus reducing the trihalomethane formation potential (THMFP). The research on recharged effluent municipal effluent below the 91st Avenue Plant in Phoenix has shown the value of nanofiltration for reclaiming municipal wastewater to potable standards. A 20,000 GPD slowsand /nanofiltration pilot plant at Apache Junction has shown the effectiveness of the treatment on Colorado River Water at a 95% recovery over the past 2 years.
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Wastewater - A ResourceAs the Southwest United States grows and develops, one basic resource becomes a primary necessity for survival: Water. Currently, accepted sources are being consumed at a higher rate than nature replenishes them. This is necessitating the need to find and develop new water resources. In conjunction with the proper treatment and management, wastewater is a water resource, known as reuse. Properly managed, reused water can augment the available water supply. Primary applications include irrigation of agricultural and landscaped areas, surface water recreational areas, and groundwater recharge. These uses relieve the demands on the generally accepted water resources, thus increasing the net water supply. The required level of treatment varies with the intended reuse application. Treatment levels for reuse range from secondary to tertiary treatment systems. Some reuse applications provide additional treatment to the water. The reuser must assure that the treatment system and reuse application provide an equal or improved water quality to that of the receiving body of water. Regardless of the application, stringent operation and maintenance of the reuse system is essential. A well planned management program will minimize hazards associated with reuse of wastewater. This program is required to keep the liabilities of both the treatment plant and reuse site owners to a minimum. Without this, reuse is not a viable option. The underlying questions remain to determine the feasibility of reuse for a community: Does the water supply require augmentation to meet the demands of the future? Is the Owner willing to address and implement a diligent system management program?
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Soil Vapor Surveys for Cost Cutting Site CharacterizationNew technical approaches and cost cutting alternatives are being utilized in the environmental engineering field. These unique methods are used in the mapping, delineation and remediation of contaminated sites. One development which has seen a sudden increase in the recent past is the utilization of soil vapor surveys to map contamination plumes in the vadose zone. Using the soil vapor method, industrial sites and sites containing potential buried drums or underground storage tanks can be quickly evaluated for the presence of volatile contaminants. This information can be especially important in property transactions where buyers desire to protect themselves from potential costly clean-ups. The soil vapor survey consists of sampling volatile vapors in the vadose zone and analysis of the vapors on analytical instruments. The survey targets those contaminants which have volatilized from residues in soils or shallow ground water. One method of sampling soil vapors is penetrating five to ten feet into the sub-surface with a sampling probe. Upon collection of the vapors, concentrations may be measured. The analytical instruments can range from simple Drager Tubes to a laboratory gas chromatograph. The methodology for selecting sampling locations depends on the site. An underground storage tank facility may be approached by completing sampling locations at the tank pit and near the product lines. A grid sampling location map may be used to sample a property with an unknown organic content. Soil vapor surveys have limitations in regards to soil types, sampling depths and constituents being analyzed. However, given the proper conditions, soil vapor surveys can provide qualitative data at lower costs than alternative methods.
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Using an Erosion Equation to Predict Sediment Yield from Overland Flow SystemsThe erosion process by overland flow was analyzed in its fundamental aspects. A general predictive erosion equation was developed by combining the conditions for conservation of mass of the sediment, boundary hydraulic shear, and the sediment transport formula of Einstein-Brown. The ability of the equation to predict sediment yield from overland flow areas was demonstrated using field data from rainfall simulator plots. Comparison of the results indicated that the erosion equation presented herein can be used to predict sediment yield from unrilled overland flow areas with satisfactory confidence.
