• 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.
    • 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.
    • 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.
    • 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.
    • Residual Waxes for Water Harvesting

      Fink, Dwayne H.; U. S. Water Conservation Laboratory, Phoenix, Arizona 85040 (Arizona-Nevada Academy of Science, 1977-04-16)
      This study was undertaken to compare the water harvesting potential of several residual waxes with that of refined paraffin. These residual waxes could possibly have advantages over refined paraffin as a soil treatment for water-harvesting catchments in that they are byproducts rather than an end product (constituting an energy savings), are slightly cheaper, and are more adhesive and less brittle. However, these residual waxes have high physical - chemical property variability which complicates testing for utility in water-harvesting. The lack of an easily obtainable ' characterization index ' is a particular deficiency. Upon laboratory testing, several of the residual waxes were found to be superior to refined paraffin in water-repellancy, structural stability, erosion and freeze-thaw resistance and ozone and ultraviolet radiation effects. The need for further laboratory and field testing was noted.
    • An Application of Multidisciplinary Water Resources Planning and Management for the San Carlos Apache Indian Reservation: Gila River Case

      Novelle, M. E.; Percious, D. J.; Wright, N. G.; Office of Arid Lands Studies, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)
      The Laboratory of Native Development, Systems Analysis and Applied Technology (NADSAT) was established to provide technical assistance to southwestern Indian Tribes as an aid in the development and use of their natural resources according to their goals and objectives. NADSAT 's role is assistance and technology transfer, with an emphasis on alternative formulation and performance analysis and communicating the technological approach to tribal decision makers. The cost-effectiveness methodology provides a coherent framework and affords a mechanism for technology transfer, which makes it a useful tool in achieving tribal goals. This method was applied to the formulation of possible alternatives for use of the land and water resources of the Gila River Basin within the San Carlos Apache Indian Reservation. Criteria for devising various alternative utilization schemes are discussed, and the advantages of the cost effectiveness methodology.
    • Variations in Soil Moisture Under Natural Vegetation

      Sammis, T. W.; Weeks, D. L.; Agricultural Engineering Department, New Mexico State University, Las Cruces; Experimental Statistics, New Mexico State University, Las Cruces, New Mexico (Arizona-Nevada Academy of Science, 1977-04-16)
      Soil water content was measured every two weeks during 1974-1975, using a neutron probe, at selected locations around the desert plant species creosote (Larria divaricata), bursage (Ambrosia deltoidea), and in an open space. The purpose of taking the measurements was to enable one to estimate the evapotranspiration rate of the desert plants by measuring soil moisture depletion. The sampling problem associated with measuring soil moisture, using neutron access tubes, is the number, location, and installation depth of the tubes. Analyses of the total soil moisture beneath the creosote plant showed greater variability between access tubes located near different plants the same distance from the crown of the plant than between tubes located around the same plant. Because of the size of the bursage plant, the variability in total soil moisture beneath the plant was greater among tubes around the same plant than between tubes at the same location at different plants.
    • 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)
    • 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.
    • 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.