• Heavy Metals & Wastewater Reuse

      Higgins, T. E.; Department of Engineering, Arizona State University, Tempe (Arizona-Nevada Academy of Science, 1978-04-15)
      Water shortages in the Western United States have intensified the search for new sources. Wastewater reuse is being increasingly called upon to augment existing supplies. One potential impediment to the continued expansion of wastewater reuse efforts is the accumulation of toxic heavy metals and other salts in the recycled water. Conventional and advanced wastewater treatment effect the removal of a portion of the heavy metals added during use. Removal is by chemical precipitation and adsorption and disposed of with the sludges. Potential uses of treated wastewater effluents include irrigation and groundwater recharge. Care must be taken to prevent contamination of groundwater, especially since existing wells have been reported to have concentrations of heavy metals in excess of drinking water standards. Percolation of wastewaters through soils (especially fine soils) results in a reduction in heavy metal concentrations. It is postulated that removal of these metals is by a combination of chemical precipitation with filtration of the precipitates, and adsorption on soil particles (thus the effectiveness of fine soils). Long term saturation of the soils with heavy metals may result in a "breakthrough" contamination of the groundwater. A predictive model of heavy metal-wastewater-soil interactions is proposed to aid in the design and regulation of wastewater reuse systems to eliminate or minimize this problem.
    • Hydrologic Factors Affecting Groundwater Management for the City of Tucson, Arizona

      Johnson, R. B.; Water and Sewer Department, City of Tucson, Arizona (Arizona-Nevada Academy of Science, 1978-04-15)
      Assessment of the basic hydrologic and geologic parameters controlling the occurrence and availability of local groundwater is one of the first steps in formulating any comprehensive water management plan. Each of several parameters must be carefully evaluated both individually and in relation to the other factors which together describe the occurrence and movement of the subsurface water resources. These evaluations are fundamental to the legal and political decision- making framework within which the Water Utility must operate for both short and long-range water management planning. Recent changes in several hydrologic parameters have been observed throughout much of the groundwater reservoir tapped by numerous users in the Tucson Basin. Accelerated water level decline rates, decreasing production capacities of existing wells, increased hydrologic interference and increased demand for water are all having an impact on our water resource. These conditions must be evaluated before basin -wide groundwater management alternatives can be implemented.
    • Hydrology and Water Resources in Arizona and the Southwest, Volume 08 (1978)

      Unknown author (Arizona-Nevada Academy of Science, 1978-04-15)
    • Land Treatment for Primary Sewage Effluent: Water and Energy Conservation

      Rice, R. C.; Gilbert, R. G.; U. S. Water Conservation Laboratory, Phoenix, Arizona 85040 (Arizona-Nevada Academy of Science, 1978-04-15)
      Land treatment of secondary municipal wastewater is an economical and aesthetic method of upgrading water quality, if hydrologic and geologic conditions are favorable. Costly conventional secondary treatment, which requires large quantities of electrical energy, can be bypassed by applying the primary effluent directly to the land. Soil- denitrifying bacteria use the organic carbon in the primary effluent as an energy source for biodenitrification and nitrogen removal. Laboratory and field studies indicated the quality of renovated wastewater meets standards for unrestricted irrigation and recreational uses. Considerable savings, both in capital and energy costs, can be realized by land treatment of primary effluent.
    • Legal Aspects of Urban Runoff Development

      Chudnoff, D. A.; Department of Hydrology and Water Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1978-04-15)
      The relationships between the separate disciplines of hydrology and law are analysed in this study into how water law and its strictures may impose upon the development of urban runoff in the metropolitan Tucson area. Brief descriptions of the doctrine of appropriation, diffuse surface waters and developed waters are presented to illustrate the complexities of the problem of urban runoff development. It is suggested that planners must not only be aware of the legal issues involved but also must understand the philosophy and principles of water law.
    • Management Alternatives for Santa Cruz Basin Groundwater

      Foster, K. E.; Office of Arid Lands Studies, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1978-04-15)
      Combined urban, agricultural, industrial and mining groundwater withdrawal from the Santa Cruz River Basin exceeds natural aquifer replenishment by 74,000 acre -feet annually. Four ameliorative water management alternatives are presented singly and in combination with one another. These alternatives are importing Colorado River water, exchanging treated effluent with mining and agricultural interests for groundwater, interbasin water transfer, and retiring farmlands for groundwater rights. These management philosophies are applicable to most economically emergent urban areas in arid and semiarid regions.
    • A Microroughness Meter for Evaluating Rainwater Infiltration

      Simanton, J. R.; Dixon, R. M.; McGowan, I.; United States Department of Agriculture, Science and Education Administration, Federal Research, Southwest Rangeland Watershed Research Center, Tucson, AZ 85705 (Arizona-Nevada Academy of Science, 1978-04-15)
      Described is a microroughness meter developed to obtain numerous and accurate measurements of rangeland surface microroughness and characteristics. The meter, which consists of four basic parts: (1) meter base and pin guide, (2) pin lifting support bar and lifting mechanism, (3) 100 vertically moving pins, and (4) stripchart support guide and winding mechanism, was designed to measure soil surface evaluations and characteristics of a 1m2 plot. Performance tests on multi-plot sprinkler infiltrometer studies conducted on the Santa Rita Experimental Range in southeastern Arizona indicated that the meter was accurate and relatively precise in repeating soil surface roughness measurements but was not precise in defining the theoretical characteristics of constructed surfaces. It was concluded, however, that these errors in precision were insignificant and due partly to surface geometry construction errors and that the meter is a convenient, quick, simple and accurate means of measuring surface roughness in studies requiring many plots and data points.
    • Nitrogen Removal from Secondary Effluent Applied to a Soil-Turf Filter

      Anderson, E. L.; Pepper, I. L.; Johnson, G. V.; Department of Soils, Water and Engineering, University of Arizona, Tucson, Arizona; Soil Testing Laboratory, Oklahoma State University, Stillwater (Arizona-Nevada Academy of Science, 1978-04-15)
      This study investigated the potential of a soil-turf filter to renovate secondary effluent applied in excess of consumptive use. Lysimeter plots were filled with a sand and a sand mix, and seeded to winter ryegrass. In spring, plots were scalped and seeded to bermudagrass. Plots were drip irrigated twice a week with secondary effluent at rates of 10, 17, 22, 34, and 43 mm/day. Leachate and effluent were analyzed for NH -N, NO,-N, and organic-N. Grass clippings were oven dried, weighed, and analyzed for organic -N. Percent of leachate available for groundwater recharge was 50% at the lowest rate and 68% at the highest rate when values were averaged for both soils. The amount of nitrogen removed by the soil-turf filter using sand was 42 to 87% and 52 to 90% on the mix, decreasing as application rate increased. The highest nitrogen removal and utilization occurred at the lowest application rate. Turf utilization of nitrogen was 10 to 28% on sand and 18 to 36% on mix, decreasing as rate of application increased. The sand-turf filter renovated 22 mm/day and the mix-turf filter renovated 43 mm/day, yielding leachate averaging less than 10 ppm NO₃-N.
    • Rainfall-Runoff Relationships for a Mountain Watershed in Southern Arizona

      Myhrman, M.; Cluff, C. B.; Putnam, F.; Water Resources Research Center, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1978-04-15)
      A network of rain gauges and two recorder -equipped flumes were installed near the head of Cottonwood Canyon on Mt. Hopkins in the Santa Rita Mountains pursuant to a water development study for the Smithsonian Institution's Mt. Hopkins Astrophysical Observatory. The watershed is generally characterized by steep slopes, a dense evergreen woodland cover predominated by several species of oaks, isolated bedrock exposures and talus chutes. The watershed for the lower flume site comprises about 145 acres (58.60 ha) with an elevation range from about 6775 to 8580 feet (2,065 to 2,615 m). Rainfall-runoff measurements were made during the summer and fall of 1977. A runoff efficiency of 0.56 percent was calculated for the lower-flume watershed. However, since physical evidence of surface flow was found only in side drainages receiving runoff from culverts located along the Mt. Hopkins access road, a second calculation was made, using only the total area of contributing road surface as the watershed area. This yielded a runoff efficiency of 27.0 percent. The latter value, adjusted for infiltration on the slopes below the culverts, agrees well with measured efficiencies for compacted-earth water harvesting catchments. Based on the above, recommendations were made for developing a water supply system using the access road, modified to increase its effectiveness, as a water harvesting system and having two surface reservoirs for storage. A computer model was used to test the capability of the system to meet the projected water needs of the observatory.
    • Rising Energy Prices, Water Demand by Peri-Urban Agriculture, and Implications for Urban Water Supply: The Tucson Case

      Ayer, H. W.; Gapp, D. W.; Natural Resource Economics Division, USDA; University of Arizona (Arizona-Nevada Academy of Science, 1978-04-15)
      The city of Tucson, Arizona, the largest city in the U.S. to meet its water needs entirely from diminishing underground sources, is presently experiencing increasing water rates and the political turmoil associated with those increases. With focus upon this increasingly serious problem, production function analysis and static linear programming are used here to estimate the impact of rising energy prices on farm profits, cropping patterns and irrigation water used in the Avra Valley, a periurban irrigated region adjacent to Tucson, in an effort to evaluate the impact of this community upon Tucson 's municipal water demand. It is concluded that as energy prices increase and land is removed from agricultural production within the Avra Valley, Tucson 's economic position will be bolstered in at least three ways: (1) there will be more water available, (2) the price which the city must pay for farmland in order to gain control of the underlying water should be diminished and the quantity of farmland for sale increased, and (3) with fewer people involved in irrigated agriculture, legal conflicts between competing users will be diminished.
    • 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.