• An Economic Analysis of the Central Arizona Project

      Barr, James L.; Pingry, David E.; Department of Economics, University of Arizona; Division of Economic and Business Research, University of Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      An economic evaluation of the Central Arizona Project was conducted with a goal of developing a simulation model of CAP costs, water operations and capital repayment alternatives. This model was compared to the actual cost experience of the Metropolitan Water District of Southern California for a realistic assessment. In addition, an effort was made to consider some of the indirect impacts of the CAP, and the overall economic outlook was summarized. In devising the simulation model CAP capital costs, CAP power supply and CAP water supply factors were considered along with user charges, management alternatives, and operations, maintenance and repair costs.
    • Effects of Brush to Grass Conversion on the Hydrology and Erosion of a Semiarid Southwestern Rangeland Watershed

      Simanton, J. R.; Osborn, H. B.; Renard, K. G.; United States Department of Agriculture, Agricultural Research Service, Western Region, Southwest Watershed Research Center, Tucson, Arizona 85705 (Arizona-Nevada Academy of Science, 1977-04-16)
      Increased nutritional and economic demands for agricultural products have dictated the need for greater and more efficient use of western grass forage. Vegetation manipulation is the quickest and most economical means of increasing forage. However , the hydrologic effects must be taken into consideration before embarking on a large scale vegetation manipulated program. This study discusses the hydrologic and erosion changes measured from a 110-acre semiarid watershed which was converted from brush to grass by root plowing and seeding. Significant changes were observed in rainfall-runoff relationships as average summer runoff was considerably in excess of predictions. Sediment yield also varied, and both of these results were tied to the change in vegetative cover and post conversion rainfall conditions.
    • A Water Supply Data Base

      Nunamaker, J. F.; Pingry, David E.; Riley, Rex; Departments of Management Information Systems and Economics, University of Arizona, Tucson, Arizona; Electric Power Research Institute, Inc., Palo Alto, California (Arizona-Nevada Academy of Science, 1977-04-16)
      This paper describes a water supply data base being developed for the Colorado River Basin States by the University of Arizona under contract with the Electric Power Research Institute, Inc. This data base is a guide to existing natural, technical, economic, and legal water data and water data agencies in the states of Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.
    • Diurnal Trends in Water Status, Transpiration, and Photosynthesis of Saltcedar

      Williams, Mary Ellen; Anderson, Jay E.; Department of Biology, Idaho State University, Pocatello, ID (Arizona-Nevada Academy of Science, 1977-04-16)
      Relative water content (RWC), water potential (P), and gas exchange were measured on saltcedar at the Bernardo, New Mexico, lysimeter site. RWC and s were closely correlated; but, water potential measurements, taken with a pressure bomb, were more convenient and reliable. RWC and r decreased sharply from sunup until about 0900, when minimum values of about -26 bars T or 80% RWC were reached. Water status then remained constant or improved slightly through late afternoon. Transpiration rates typically remained high until about noon and then began a steady, gradual decrease that continued throughout the afternoon. The data suggest that water stress may be a factor in initiating stomatal closure; however, transpiration continued to decline despite a constant or improved leaf water status. Maximum net photosynthetic rates occurred by 0900, and depressions throughout the remainder of the day were largely accounted for by increased leaf temperatures. Afternoon depressions in transpiration and photosynthesis occurred in twigs held at constant temperature and relative humidity, suggesting that a diurnal rhythm may be involved in control of gas exchange. Water status of plants growing on the lysimeters was comparable to that of plants in adjacent natural stands; gas exchange rates were slightly higher for the lysimeter-grown plants.
    • Transpiration and Photosynthesis in Saltcedar

      Anderson, Jay E.; Department of Biology, Idaho State University, Pocatello, ID (Arizona-Nevada Academy of Science, 1977-04-16)
      Factors controlling transpiration and photosynthesis of saltcedar were investigated in the field near Bernardo, New Mexico. Transpiration rates were similar to those for several herbaceous species, but photosynthesis and water use efficiency were significantly lower in saltcedar. Photosynthesis was light saturated at an irradiance equal to 44% of full sunlight, while the stomata were apparently fully open at light levels greater than one-third full sunlight. Optimum leaf temperatures for photosynthesis were between 23° and 28 °C, considerably lower than typical daytime ambient temperatures. Photosynthesis was reduced about 20% at 35 °C. Stomatal resistance increased linearly with increases in leaf temperature between 14° and 50 °C, with relative humidity held constant. The increase in stomatal resistance could have been caused by direct effects of temperature on the stomata, by increases in the absolute humidity gradient from leaf to air, or by both. Increased stomatal resistance at high temperatures and low relative humidities would account for observed afternoon depressions in transpiration and photosynthesis and increases in canopy resistance. Estimates of stomatal resistance for twigs in full sunlight ranged from 2 to 6 sec cm⁻¹, with most values falling between 3 and 5 sec cm-, when leaves were at 30 °C.
    • The Arizona Water Commission's Central Arizona Project Water Allocation Model System

      Briggs, Philip C.; Arizona Water Commission, Phoenix, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      The purpose and operation of the Central Arizona Project water allocation model system are described, based on a system analysis approach developed over the past 30 years into an interdisciplinary science for the study and resolution of complex technical management problems. The system utilizes mathematical and other simulation models designed for computer operations to effectively solve such problems as the CAP faces including those concerned with social and economic considerations. The model is composed of two major components: (1) a linear program designed to determine the optimal allocation of all sources of water to all demands and, (2) a hydrologic simulator capable of reflecting the impact of distribution alternatives on per-unit cost of delivery. The model, currently being use, has substantially contributed to a greater understanding of water usage potential in Arizona.
    • Effect of Illuviated Deposits on Infiltration Rates and Denitrification During Sewage Effluent Recharge

      Montgomery, Errol L.; Korkosz, Emily; Dalton, Russell O., Jr.; DeWitt, Ronald H. (Arizona-Nevada Academy of Science, 1977-04-16)
      This study, conducted to determine the interrelationships among nitrogen transformations, infiltration rates, and development of the black layer found in the Santa Cruz River downstream of the Tucson (Arizona) sewage treatment plant, tested these interrelationships by percolating sewage effluent through clear acrylic columns uniformly packed with river sand for the first run, with gravel for the second run. Sewage effluent was continuously applied to three of the columns for 28 and 64 days during the first and second runs respectively. The remaining column was continuously flooded with tap water to serve as a control. Infiltration rates decreased rapidly upon application of the sewage, and within a few days a black layer developed, its thickness inversely related to the infiltration rate but not a cause of reduced flow, which is attributed, rather, to clogging of the surface by suspended solids. There was an average reduction in total nitrogen of 62.9% for the first run, and 15.9% for the second. The mechanisms of removal for run 1 were predominately absorption and denitrification, whereas the predominate removal mechanism in run 2 was filtering of organic nitrogen with adsorption and denitrification also playing an important role.
    • Soil Erosion and Sediment Control on the Reclaimed Coal Mine Lands of the Semi-arid Southwest

      Verma, Tika R.; Thames, John L.; Mills, John E.; School of Renewable Natural Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1977-04-16)
      Extensive disturbances are expected during the remainder of this century due to strip mining in the semi-arid West. Reclamation and revegetation of these disturbed areas is a slow process, primarily due to dry and harsh climatic conditions. Erosion and sediment losses are high. Monitoring of the soil erosion process is a crucial step in planning for a long lasting and stable rehabilitation of these disturbed areas. Erosion plots have been laid out to collect data for the Universal Soil Loss Equation for estimating soil loss from recontoured coal mine spoils. Effectiveness of different cultural and mechanical treatments for erosion control is also being evaluated. Since large-scale coal mining operation has just begun on the Black Mesa, preliminary data could be very effective and useful in Watershed Management planning.
    • A Utility Criterion for Real-time Reservoir Operation

      Duckstein, Lucien; Krzysztofowicz, Roman; Departments of Systems and Industrial Engineering and Hydrology & Water Resources, University of Arizona, Tucson, AZ 85721; Department of Hydrology and Water Resources, University of Arizona, Tucson 85721 (Arizona-Nevada Academy of Science, 1977-04-16)
      A dual purpose reservoir control problem can logically be modelled as a game against nature. The first purpose of the reservoir is flood control under uncertain inflow, which corresponds to short -range operation (SRO); the second purpose, which the present model imbeds into the first one, is water supply after the flood has receded, and corresponds to long-range operation (LRO). The reservoir manager makes release decisions based on his SRO risk. The trade-offs involved in his decision are described by a utility function, which is constructed within the framework of Keeney's multiattribute utility theory. The underlying assumptions appear to be quite natural for the reservoir control problem. To test the model, an experiment assessing the utility criterion of individuals has been performed; the results tend to confirm the plausibility of the approach. In particular, most individuals appear to have a risk-averse attitude for small floods and a risk-taking attitude for large ones.
    • Stable Isotopes of Oxygen in Plants: A Possible Paleohygrometer

      Ferhl, A. M.; Long, A.; Lerman, J. C.; University "Pierre & Marie Curie", Department of Earth Sciences, Paris, France; Laboratory of Isotope Geochemistry, Department of Geosciences, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1977-04-16)
      Ratios of oxygen-18 to oxygen-16 in cellulose of dated rings from trees grown in nature and from plants grown in controlled environments have significance for retrieving information about the environment in which they grew. Phaseolus vulgaris was grown under varying conditions of controlled temperature, humidity and ¹⁸O/ ¹⁶O of irrigation water. The ¹⁸O/ ¹⁶O in plant tissue responds mostly to different environmental relative humidity; plant tissue grown under conditions of low relative humidity produce tissue relatively high in oxygen-18. Reasons for this response are not clear to us, but the relationship may prove a useful complement to established dendroclimatologic techniques.
    • Nonpoint-Source Pollutants to Determine Runoff Source Areas

      Lane, L. J.; Norton, H. L.; Wallace, D. E.; Wilson, R. E.; Martin, R. D.; USDA, ARS, Tucson, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      Hydrologic information is needed to understand and control water pollution from semiarid rangelands. However, the hydrologic systems under any given conditions must be understood and the effects of various land uses predicted. Based on the concept of partial area response, a runoff tracer study was conducted on two small watersheds. The watersheds were partitioned into four geomorphic subzones or hydrologic response units. Each of the four zones on both watersheds was treated with about 1 kg/ha of an individual water soluble herbicide. Runoff volumes and sources estimated using the tracers were consistent with results from simulation studies. Also, the principle of corresponding runoff and pollutant discharge rates was used to develop two methods of runoff hydrograph estimation from each of the geomorphic subzones. Method 1 matched the mean total concentration and total runoff volume. Method 2 matched the instantaneous total concentration and the instantaneous runoff rate from the entire watershed. Results from the two methods suggested that, although they may be equivalent with respect to runoff volume, Method 2 may be more consistent with respect to peak discharge.
    • A Land Imprinter for Revegetation of Barren Land Areas Through Infiltration Control

      Dixon, R. M.; Simanton, J. R.; United States Department of Agriculture, Agricultural Research Service, Western Region, Southwest Watershed Research Center, Tucson, Arizona 85705 (Arizona-Nevada Academy of Science, 1977-04-16)
      A new minimum tillage implement, "the land imprinter," has been designed and fabricated, and is currently being tested. Its design is based on water infiltration control theory developed during the past decade. The land imprinter was developed primarily for establishing vegetation in barren land areas in semiarid and arid regions of the world. It simultaneously forms interconnected downslope and cross - slope corrugations that shed water and then infiltrate it precisely where vegetative growth is to be encouraged. This controlled short distance routing of water along short waterways into small reservoirs makes more rainwater available for seed germination and seedling establishment, and less water available for loss by surface runoff and evaporation. The imprinter has only one moving part, in the form of a massive compound roller and central axle which turn together as a rigid assembly during operation. The compound roller consists of two imprint capsules which are linked together on the axle shaft by an axle pulling clamp. The core of the imprint capsule is a hollow steel cylinder (1-m diameter and 1-m long) fabricated from 1.27-cm steel plate. A variety of imprint geometries are formed by welding short lengths of specially -cut steel angles (1.27 cm x 15.24 cm x 15.24 cm) to the outer surface of the cylindrical core. Ten imprint capsules with distinctly different geometric patterns of steel angles have been developed and fabricated. By pairing these capsules in as many ways as possible, 45 different geometric patterns can be imprinted. The patterns of steel angles perform a number of different tillage functions including (1) brush and soft rock crushing, (2) brush and rock imbedding, (3) runoff inducing and directing, (4) infiltration inducing and directing, (5) biomass concentrating, (6) seedbed forming, (7) surface and vertical mulching, (8) wind and water erosion controlling, (9) surface compacting, and (10) surface trenching and pitting. Advantages of the land imprinter as compared with alternative tillage methods include (1) greater stability, diversity, complexity, and precision of surface geometric patterns; (2) better control of point infiltration, runoff, erosion, and evaporation; and (3) greater utility in brush -covered, steeply - sloping, deeply gullied, and rocky land. The land imprinter should have widespread utility in both range and croplands because of its unique ability to mold runoff -watered seedbeds that increase the probability of seed germination and seedling establishment.
    • Root System of Shrub Live Oak in Relation to Water Yield by Chaparral

      Davis, Edwin A.; USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, Tempe, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      The root system of shrub live oak (Quercus turbinella) was studied in an initial effort to classify the major Arizona chaparral shrubs as potential users of soil water based on root system characteristics. The root system was of the generalized type with a taproot, many deeply penetrating roots, and a strong lateral root system. Roots penetrated 21 feet to bedrock through cracks and fractures in the rocky regolith. A dense network of small surface laterals radiated from the root crown and permeated the upper foot of soil. Because of its root system, shrub live oak is well adapted to utilize both ephemeral surface soil moisture as well as deeply stored moisture. Emphasis is placed on the importance of a knowledge of the root systems of chaparral shrubs and depth of the regolith in planning vegetation conversions to increase water yield.
    • Estimating Phreatophyte Transpiration

      Gay, Lloyd W.; Sammis, Theodore W.; School of Renewable Natural Resources, The University of Arizona, Tucson; Department of Agricultural Engineering, New Mexico State University, Las Cruces (Arizona-Nevada Academy of Science, 1977-04-16)
      Phreatophyte transpiration on the Colorado River floodplain in western Arizona was evaluated under hot, dry, midsummer weather conditions. The simple transpiration model used related transpiration to the vapor pressure deficit of the air and to the area and the diffusion resistance of the transpiring foliage. There were no independent transpiration measurements for verification of the results. On a relative basis, however, mesquite (Prosopis sp.) transpired more rapidly per unit of leaf area than did saltcedar (Tamarix chimensis, Lour.).
    • Influence of Forest Density on Bedload Movement in a Small Mountain Stream

      Heede, Burchard H.; USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, Tempe, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      In contrast to three ephemeral streams in the vicinity, Tony Bear Creek, a small perennial stream in the White Mountains of Arizona, showed strong relationships among parameters of hydraulic geometry. Distances between gravel bars and log steps showed an inverse relationship with gradient (r² = 0.95). Shape factor and width-depth ratio increased upstream (r² = 0.98 and 0.90, respectively), indicating depth decrease toward the headwaters. The longitudinal profile is concave, and small, infrequent channel bars suggest that sediment movement is small. In contrast to the ephemeral streams, Tony Bear Creek is thus judged to be in dynamic equilibrium. Proportion of log steps to total steps (gravel bars plus logs) was much smaller in Tony Bear Creek (about 16 %) than in five other mountain streams (about 50 %). While all other streams ran through dense forests, only 60% of Tony Bear Creek was in forest, of which 13% had been selectively cut. Thus, forest density determined the proportion of logs incorporated into the stream hydraulic system, which in turn affects bedload movement.
    • Distribution of Precipitation on Rugged Terrain in Central Arizona

      Osborn, Herbert B.; David, Donald Ross; USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, Tempe, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      A 3-year study was conducted using tilted, vertical, directional, and recording rain gages (52 in all) to evaluate rainfall distribution on the Three Bar experimental watersheds in central Arizona. The tilted gages did not improve the determination of mean areal precipitation on the small watersheds because about as many tilted gages caught less rain as caught more. Although rugged and steep, the local topography exerted only minor effects on rainfall distribution compared to the major influence exerted by the Mazatzal Mountains to the windward (southwest). Forty-nine percent of wind travel was from the southwest quarter and wind averaged 4.4 mph when rain was actually falling. Wind exceeded 10 mph 9 percent of the time and 15 mph 0.4 percent of the time. Mean annual precipitation on the 600-acre study area ranged from 30 inches at 5,000 feet elevation to 22 inches at 3,400 feet (5 inches per 1,000 feet). Results of this study indicate that precipitation averages about 36 inches at 6,200 feet elevation along the Mazatzal crest near Four Peaks, about 6 inches more than published data show for the site.
    • Reducing Phreatophyte Transpiration

      Davenport, David C.; Department of Land Air and Water Resources, University of California, Davis (Arizona-Nevada Academy of Science, 1977-04-16)
      Transpiration rates (T) of riparian phreatophytes can be high. Antitranspirant (AT) sprays can curtail T without the ecological imbalance made by eradication. Saltcedar (Tamarix sp.) and cottonwood (Populus sp.) in 15-gal. drums enabled replicated trials on isolated plants or on canopies. T of isolate saltcedar plants could be 2x that of plants in a fairly dense canopy. T for a unit ground area of saltcedar varied from 2.2 (sparse -) to 15.8 (dense-stand) mm/day in July at Davis. Extrapolation of experimental T data to field sites must, therefore, be made carefully. Wax -based ATs increased foliar diffusive resistance (R), and reduced T of saltcedar and cottonwood 32-38% initially and 10% after 3 weeks. R increased naturally in the afternoon when evaporative demand was high and if soil water was low. Nocturnal T of salt cedar was 10% of day T. AT effectiveness increased with a higher ratio of day: night hours, and with lower soil water stress. Therefore, AT will be most effective on long summer days in riparian areas where ground water is available.
    • Simulation of Summer Rainfall Occurrence in Arizona and New Mexico

      Yakowitz, Sidney; Southwest Watershed Research Center, Agricultural Research Service, Tucson, Arizona; Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      Thunderstorms produce most of the annual rainfall and almost all runoff from arid and semiarid rangelands in the southwest U.S. A model was developed to be used for predicting runoff in river basins, flood plane zonings, estimating flood damage, erosion, and sediment transport, and estimating precipitation available for forage growth. This rainfall occurrence model has three parameters: elevation, latitude and longitude, and takes into account rainfall occurrence in 22 stations located in Arizona and New Mexico. From these variables, mathematical equations were developed in an effort to predict point rainfall occurrence. Estimates of the number of seasonal occurrences were used as a check of the equations within the model.
    • Barometric Response of Water Levels in Flagstaff Municipal Wells

      Hibbert, Alden R.; Department of Geology, Northern Arizona University; Harshbarger and Associates, Tucson, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)