• Salvaging Wasted Waters for Desert-Household Gardening

      Fink, D. H.; Ehrler, W. L.; U. S. Water Conservation Laboratory, Phoenix, Arizona 85040 (Arizona-Nevada Academy of Science, 1978-04-15)
      With the objective of determining if sufficient water would be salvaged by a typical desert, urban-household from normally wasted sources associated with the lot and household to adequately irrigate a garden and orchard, a 2000 sq ft house on a typical one fifth acre lot in three cities having climates similar to Phoenix, Tucson, or Prescott, Arizona was hypothesized and the amount of water available for yard watering calculated, provided that (1) only rainfall was available, (2) rainfall-runoff from covered areas associated with or adjacent to the lot was salvaged (roof, street, alley etc.), (3) gray-water from the household was utilized, (4) a portion of the lot was waterproofed to concentrate the runoff on the untreated portion, and (5) various combinations of the above were utilized to increase the amount of available water. It is demonstrated that these sources could be used singly or in combination to obtain the required amount of water with the actual amount available depending upon the precipitation, runoff and runon areas, runoff efficiency of the contributing area, and the number of people in the household. A number of horticultural plants are suggested that should best fit such an irregular irrigation scheme.
    • A Sediment Yield Equation from an Erosion Simulation Model

      Shirley, E. D.; Lane, L. J.; Southwest Watershed Research Center, Tucson, Arizona 85705 (Arizona-Nevada Academy of Science, 1978-04-15)
      Sediment is widely recognized as a significant pollutant affecting water quality. To assess the impact of land use and management practices upon sediment yield from upland areas, it is necessary to predict erosion and sediment yield as functions of runoff, soil characteristics such as erodibility, and watershed characteristics. The combined runoff-erosion process on upland areas was modeled as overland flow on a plane, with rill and interrill erosion. Solutions to the model were previously obtained for sediment concentration in overland flow, and the combined runoff-erosion model was tested using observed runoff and sediment data. In this paper, the equations are integrated to produce a relationship between volume of runoff and total sediment yield for a given storm. The sediment yield equation is linear in runoff volume, but nonlinear in distance and, thus, watershed area. Parameters of the sediment yield equation include the hydraulic resistance parameter, rill and interrill erodibility terms, and flow depth-detachment coefficient and exponent.
    • Simple Time-Power Functions for Rainwater Infiltration and Runoff

      Dixon, R. M.; Simanton, J. R.; Lane, L. J.; Science and Education Administration, Southwest Rangeland Watershed Research Center, Tucson, AZ 85705 (Arizona-Nevada Academy of Science, 1978-04-15)
      The equations of Darcy, Kostiakov, Ostashev, Philip, and four modified Philip equations were evaluated for use in predicting and controlling rainwater infiltration and rainfall excess in crop and rangelands. These eight equations were least- square fitted to data from ring, border-irrigation, closed-top, and sprinkling infiltrometers. Kostiakov's equation satisfied the evaluation criteria better than the other seven equations. The parameters of Kostiakov's equation were physically interpreted by relating their magnitudes to some physical, biological, and hydraulic characteristics of the infiltration system. These characteristics included several infiltration abatement and augmentation processes and factors that are controlled at the soil surface by land management practices. The eight equations were also fitted to rainfall data to permit calculating runoff from small surface areas about the size of a typical crop plant. Comparison of the regression curves for infiltration and rainfall suggested that land management practices that appropriately alter the soil surface will permit wide-range control of infiltration, runoff, and erosion; and thereby achieve conservation and more efficient use of soil and water resources for crop production. The most important soil surface conditions affecting infiltration were microroughness, macroporosity, plant litter, and effective surface head.
    • Solar Radiation as Indexed by Clouds for Snowmelt Modeling

      McAda, D. P.; Ffolliott, P. F.; School of Renewable Natural Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1978-04-15)
      In an effort to improve the methods of forecasting the amount and timing of snowmelt, a primary source of water in Arizona, significant regression equations are developed over a selected measurement period to relate global, direct, and diffuse solar radiation to: (1) the cloud-cover of specific cloud genera, (2) the hour before or after solar noon, and (3) the potential solar radiation. Three regression equations are derived from cloud-cover imagery and solar radiation data collected from two sites in Arizona 's Ponderosa pine forests, Schnebly Hill, and Alpine, in the hope that regression models will be useful in the simulation of snowpack dynamics.
    • Tucson's Tools for Demand Management

      Davis, S. T.; Water and Sewer Department, City of Tucson, Arizona (Arizona-Nevada Academy of Science, 1978-04-15)
      Tucson's "Beat the Peak" program implemented in the summer of 1977 effectuated a reduction in peak day water usage from 151.5 million gallons per day on July 9, 1976, to 114.0 million gallons per day on July 8, 1977. This twenty-five percent reduction, if maintained, will allow a three -year deferral of a new remote wellfield and transmission pipeline estimated to cost between $25 and $50 million. More time will be available to analyze the cost effectiveness of solutions to the region's water resources supply problems (such as imported groundwater, Central Arizona Project water, effluent reuse, and their interrelationships). Although conservation was not promoted, the successful peak management program resulted in a 13.3 percent reduction in 1977 water use during the summer months (May through August) compared to usage during the same period in 1976. This resulted in water sales revenues less than projected, but the combination of less utility expenses and deferred capital improvements will yield lower customer rates and monthly bills than would have otherwise been necessary without the program.
    • Wastewater Effluent - An Element of Total Water Resource Planning

      Goff, J. D.; Boyle Engineering Corporation, Phoenix Brance Office (Arizona-Nevada Academy of Science, 1978-04-15)
      Wastewater reuse options for the Phoenix area include: agricultural irrigation, fish and wildlife enhancement, ground water recharge, industrial processing and coiling water, recreation, cooling water for power generation stations, and exchanging effluent for additional water supplies. Consideration is given to effluent reuse potential as a commodity to exchange for water suitable for domestic water supply. This exchange would result in yet additional reuses of the water as title to the effluent could be assured by contracts and agreements.
    • Wastewater Reuse - How Viable is It? Another Look

      Chase, W. L.; Fulton, J.; Phoenix Urban Study, U. S. Army Corps of Engineers; Phoenix Office of Stevens, Thompson, and Runyan, Inc. (Arizona-Nevada Academy of Science, 1978-04-15)
      Even though the Phoenix Metropolitan Area is more fortunate than other areas of the desert southwest because of the dependable Salt and Verde River supplies, they still have water problems. The Central Arizona Project (CAP), which will bring water from the Colorado River, will help those problems. But the CAP will not eliminate them. Improved water resource management will be required to bring water supply and demand back into balance. A key element of any successful water resource management program must be wastewater reuse. The communities are studying reuse through their 208 water quality program and while they are discovering that many opportunities exist they are also discovering that there are also many problems to be solved.
    • Water Quality of Runoff from Surface Mined Lands in Northern Arizona

      Kempf, J.; Leonhart, L.; Fogel, M.; Duckstein, L.; Department of Systems and Industrial Engineering, University of Arizona, Tucson; School of Renewable Natural Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1978-04-15)
      Surface mining of coal in the western U.S. can cause problems of increased salinity and heavy metal contamination in runoff along with a lack of enough rainfall to sustain plant growth for reclamation. To facilitate the planning of reclamation efforts in such areas results are described of a water quality sampling experiment on the ponds and runoff at the University of Arizona Experimental Watershed on Black Mesa in northern Arizona. A systems theoretic framework is employed to model the watershed and the results of a computer simulation based on this model is used to indicate that salinity buildup could be expected over time, given a minimal change in watershed configuration, with possible development of fluoride contamination being of particular concern. Water quality tests of the pond water and runoff on Black Mesa indicated that the water is within Federal standards for drinking and irrigation, except for sodium and fluoride. It is suggested that if it is economically desirable, the collection of more data on the ponds could be used to develop a simulation model of pond subsystems along the lines of the methodology outlined in this analysis.
    • Water Quality Problem of the Urban Area in an Arid Environment, Tucson, Arizona

      Hansen, G.; Pima Association of Governments, 208 Water Quality Management Program (Arizona-Nevada Academy of Science, 1978-04-15)
      The U.S. Environmental Protection Agency 's two-year 208 area-wide Water Quality Management Study for Pima County, Arizona, is discussed in terms of the specific problems of municipal wastewater effluent, industrial wastewater, urban stormwater runoff, land disposal of residual wastes, septic systems, and construction activities related to the City of Tucson urban area. The primary groundwater and the slow cycling of the hydrologic system in this arid urban environment reduce many water pollution problems to insignificant levels in the short term, (2) there does exist significant long-term pollution problems in the area. These problems include urban stormwater runoff and landfill leachate, and are related to the pollution of groundwater recharge and aquifer water supplies, and (3) there is a strong need for total water resource planning in arid urban areas which includes planning for wastewater reuse, water harvesting, and proper management of groundwater recharge systems.