• Erosion and Sedimentation in the Upper Gila Drainage, A Case Study

      Kingston, R. L.; Solomon, R. M.; Gila National Forest, Silver City, New Mexico (Arizona-Nevada Academy of Science, 1976-05-01)
      The upper Gila River in Arizona and New Mexico contains extremely diverse geology and soils. One geological formation that is somewhat unique to the Southwest and the upper Gila drainage is the Gila Conglomerate formation. In New Mexico, this conglomerate is extensive on the main Gila River drainage, accounting for over 35 percent of the main basin area. A case study was done on the 22,580 hectare (55,793 acres) Lake Roberts Watershed to assess the current sedimentation problem and its sources. This study revealed interesting patterns of lake surface area changes with volume changes of the original 28.3 hectare (70 acres) man-made reservoir over the last 12 years. Surface area reduction (19%) has progressed at a rate over twice that for volume reduction (9%). The source of the problem stems primarily from soils derived from highly sensitive Gila Conglomerate. The watershed is not uncharacteristic of the unique geology and soils typical of the upper Gila drainage and may furnish insight into sediment production and sources for much of the Gila headwater drainage in New Mexico.
    • An Energy Budget Analysis of Evapotranspiration from Saltcedar

      Gay, L. W.; Sammis, T. W.; Ben-Asher, J.; School of Renewable Natural Resources, University of Arizona, Tucson; Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona; Water Resources Research Center, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1976-05-01)
      Energy budget evaluations of evapotranspiration from saltcedar were carried out on the flood plain of the Rio Grande River, near Bernardo, New Mexico. The site was adjacent to the Bureau of Reclamation's lysimeter study of water use by saltcedar. The energy budget for the cloudless day of June 14, 1975, revealed that energy gains from net radiation totaled 432 cal/cm² , while energy losses (in cal/cm2 ), were 14 to stored energy, 31 to convection, and 387 to evapotranspiration (ET). The energy loss to ET is equivalent to the latent energy contained in about 6.5 mm of water. The energy budget values are reasonable for a phreatophyte community in a semi-arid environment. The latent energy loss compares favorably with 401 cal/cm² measured by three lysimeters, although there were discrepancies in timing and amounts of loss among the individual lysimeters. The mean canopy diffusion resistance was 1.90 sec/cm over a 10-hour daytime period on June 14. The mean resistance was combined with vapor pressure deficit to predict lysimeter ET on three subsequent days. The agreement was within 12 percent, which suggests that diffusion resistance may be useful for simple ET predictions.
    • Evaluation of Recharge Through Soils in a Mountain Region: A Case Study on the Empire and the Sonoita Basins

      Kafri, U.; Ben-Asher, J.; Water Resources Research Center, University of Arizona, Tucson 85721 (Arizona-Nevada Academy of Science, 1976-05-01)
      A conventional water balance method, employing long-term average values of rainfall, runoff and evapotranspiration yields near-zero recharge values for the Empire and the Sonoita basins. These results, however, are not in agreement with those obtained from an analysis of the local ground water regimes. A different approach for calculating recharge, based on the typical characteristics of these arid basins, is proposed. In particular, both basins are characterized by intense thunderstorms of short duration in the summer which occur usually towards the evening, and shallow, sandy-gravelly soils with a relatively high permeability overlying fractured rocks in the elevated mountain regions. These factors may cause a considerable amount of water to infiltrate through the soil profile, thereby escaping evapotranspiration during the following day. The proposed model deals with separate thunderstorm events using mean values of rainfall intensity and frequency corresponding to elevation. This model was coupled with a numerical solution of the flow equation which was used to solve the one dimensional water flow through a soil profile. The solution includes sink terms and was solved for the simultaneous processes of infiltration, moisture redistribution and evapotranspiration. The results obtained show almost no recharge in the low valleys, but significant recharge in the mountains. The amount of recharge increases with elevation and decreases with the depth of the soil profile.
    • Geomorphic Thresholds and Their Influence on Surface Runoff from Small Semiarid Watersheds

      Wallace, D. E.; Lane, L. J.; Southwest Watershed Research Center, Tucson, Arizona 85705 (Arizona-Nevada Academy of Science, 1976-05-01)
      The geomorphic threshold concept of landform evolution and its effect on hydrologic performance of drainage systems was investigated on small semiarid watersheds in Southeastern Arizona. Thresholds develop within a geomorphic system with time and can, when exceeded, cause drastic changes in the geomorphic features and in the hydrologic performance of the watershed. The slow continuous evolution of drainage characteristics can be suddenly altered with major readjustment of the landscape taking place. A new state of dynamic equilibrium will then prevail until the drainage system is again subjected to conditions which cause some geomorphic threshold to be exceeded. Areas of potential geomorphic readjustment can be identified from parameters such as channel slope, average land surface slope, drainage density, and mean length of first order streams and these data can be used as components in a calibrated kinematic-cascade model to determine the effects of various degrees of drainage system alteration. The influence on runoff from exceeding various geomorphic thresholds is tested and the resulting hydrologic modifications are simulated and discussed.
    • Addition of a Carbon Pulse to Stimulate Denitrification in Soil Columns Flooded with Sewage Water

      Lance, J. C.; Gilbert, R. G.; U. S. Water Conservation Laboratory, Phoenix, Arizona 85040 (Arizona-Nevada Academy of Science, 1976-05-01)
    • Planning Models of an Irrigated Farm with Limited Water

      Blank, Herbert G.; Agency for International Development, Sana, Yemen (Arizona-Nevada Academy of Science, 1976-05-01)
    • Water Quality Study of Lake Havasu, Arizona Near the CAP Intake Area

      Ince, Simon; Kreamer, David L.; Young, Don W.; Constant, Charles L.; Department of Hydrology and Water Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1976-05-01)
      Throughout 1974 and 1975 the Department of Hydrology and Water Resources, University of Arizona, conducted a water quality study on Lake Havasu, Arizona, near the Central Arizona Project intake. This investigation was funded jointly by the Arizona Water Commission and the U.S. Bureau of Reclamation. The University study evaluated the hydrography and hydrology, sediments, turbidity, temperature, chemistry, dissolved oxygen (and biochemical oxygen demand), benthic invertebrates, phytoplankton, zooplankton, biomass analysis, and electrical conductivity to establish baseline data for the CAP intake area. The results showed weak stratification and generally good aeration in the lake and high turbidity in the Bill Williams River. Biological quality was good with low amounts of benthics and numerous zooplankton and phytoplankton species. The extensive data from chemical analysis generally conformed to public health standards.
    • Politics of Water in Arizona

      Farr, Morris (Arizona-Nevada Academy of Science, 1976-05-01)
    • Application of Carbon-14 Ground-Water Ages in Calibrating a Flow Model of the Tucson Basin Aquifer, Arizona

      Campana, Michael E.; Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1976-05-01)
      In the absence of pure piston flow, the carbon-14 ages of ground-water can be related to groundwater residence times only in the context of a flow model. To do this, a three-dimensional digital computer model of a portion of the Tucson Basin Aquifer was constructed using the theory of finite-state mixing cell models. The model was calibrated against the spatial distribution of adjusted carbon-14 ground-water ages, and once a reasonable fit was obtained, the ground-water residence times were calculated. The model also provides a first approximation to three-dimensional flow in the aquifer as well as an estimate of the long-term average annual recharge to the aquifer.
    • The Effect of an Intensive Summer Thunderstorm on a Semiarid Urbanized Watershed

      Boyer, D. G.; DeCook, K. J.; Water Resources Research Center, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1976-05-01)
      The University of Arizona Atterbury Experimental Watershed, located southeast of Tucson, Arizona has been instrumented for precipitation and runoff measurements since 1956. Early on the afternoon of July 16, 1975 an intense convective thunderstorm produced more than three inches of rainfall in less than 50 minutes as recorded in several rain gages located in the middle of one 8.1 square-mile desert subwatershed. Storm runoff from this rural subwatershed and an adjacent recently urbanized subwatershed filled the newly finished Lakeside Reservoir and topped the concrete flood spillway with a peak of greater than 3000 cfs, the greatest flow since monitoring began. An analysis of storm characteristics, along with previously available data from local urbanized watersheds, allows speculation on the effect of such an intensive storm in a highly urbanized area.
    • Resolutions of Analog Rainfall Records Relative to Chart Scales

      Chery, Donald L, Jr.; Beaver, Dave G.; USDA, Agriculture Research Service, Western Region, Southwest Watershed Research Center, Tucson, Arizona 85705; Soils, Water and Engineering Department, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1976-05-01)
      Five rainfall distributions, four l-in rainfall depths and one 3-in rainfall depth were plotted on charts with five different combinations of time and depth scales. The plotted events were read on an analog-to-digital converter by four different researchers. Each reading of a plotted record was compared with the known simulated rainfall-rate distribution. The correspondence of the rainfall rates read from the charts with the actual rainfall rate distribution is measured by an integral squared error and correlation coefficient. The results showed a general correspondence between error and the chart scale and a strong influence of maximum recorded rate and rate distribution on the error. For the chart scales evaluated, error did not become more directly associated with scale, except when recorded rates were less than about 10 in/hr. Error was directly related to the number of points read in any given trace by the relation E = 16.3N^(-0•426).
    • Water-Related Information Sources: Highlights

      White, Linda M.; Center for Quantitative Studies, The University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1976-05-01)
    • Determining Areal Precipitation in the Basin and Range Province of Southern Arizona - Sonoita Creek Basin

      Ben-Asher, J.; Randall, J.; Resnick, S.; Water Resources Research Center, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1976-05-01)
      A linear relationship between point precipitation and elevation in conjunction with a computer four-point interpolation technique was used to simulate areal rainfall over Sonoita Creek Basin, Arizona. The simulation's sensitivity and accuracy were checked against the official isohyetal map of Arizona (Univ. of Arizona, 1965) by changing the density of the interpolation nodes. The simulation was found to be in good agreement with the official map. The average areal-rainfall was calculated by integration. Cumulative rainfall amounts were assumed to be stochastically independent from one season to another. The seasonal precipitations of forty years (1932-1972) were subdivided into five groups. to check for binomial distribution. The binomial model fits the historical data adequately. The binomial model for cumulative seasonal areal-precipitation provides one way to compute the return period. This information will be necessary for decision-makers and hydrologists to predict the area's future water balance.
    • Future Effects of the CAP on Lake Havasu's Thermal Regime

      Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1976-05-01)
      A temperature-stratification model developed by the U. S. Army Corps of Engineers, Hydrologic Engineering Center, was used to predict the changes in the temperature profile of Lake Havasu on the Colorado River near Parker, Arizona, that may occur with the withdrawal of Central Arizona Project (CAP) water in the 1980's. This quantified change in temperature-dependent density stratification was calculated using maximum withdrawal conditions to accentuate and expose any major changes which could be potential problems. Inputs for this program include monthly evaporation and precipitation, monthly average air temperature, solar radiation at the top of the atmosphere, water inflow amount and temperature, water outflow amount and location, water temperature profiles, and physical reservoir data. In the calibration of the model, the five coefficients were found to differ slightly from regional coefficients established by the Hydrologic Engineering Center, Davis, California, and coefficients established in a previous study. End of month temperature profiles were then generated for average meteorological conditions, both with and without maximum CAP flow. The computed results indicate that the stratification changes will be of low magnitude.
    • Academic Training for Groundwater Quality Specialists

      Schmidt, Kenneth D. (Arizona-Nevada Academy of Science, 1976-05-01)
    • Arizona Water: Uses and Sources Past, Present, and Future

      Davidson, Lucy (Arizona-Nevada Academy of Science, 1976-05-01)
    • Systematic Assessment of Uncertainties in an Environmental Impact Statement

      Nnaji, Soronadi; Davis, Donald R.; Duckstein, Lucien; Department of Hydrology & Water Resources and Systems and Industrial Engineering (Arizona-Nevada Academy of Science, 1976-05-01)
      An environmental impact statement (EIS) is meant to be a predictor of the consequences of actions on the environment. However, uncertainties in the statements make it difficult to determine the reliability of the predictions and thus the consequences of the actions. Hence, use of an EIS could be counter-productive if the inherent uncertainties are not recognized and considered in its evaluation. Examination of several EIS's from a systems viewpoint is used to expose the following sources of uncertainty: (1) the identification of the components of the system, (2) the natural uncertainty of the inputs to the system and of the transformation functions producing the output, (3) uncertainties in the modeling of the system due to limitations of sample, economic and technological data. The above viewpoint is used to analyze the Colorado River Salinity Control Project EIS. Uncertainties are identified and classified and means for assessing and incorporating their effect on the environmental impact assessment are discussed.
    • Feasibility of Using Solar Energy for Irrigation Pumping

      Larson, Dennis; Fanmeier, D. D.; Matlock, W. G.; Day, John; Sands, C. D., II; Soils, Water and Engineering Department, University of Arizona, Tucson, Arizona; Agricultural Economics Department, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1976-05-01)
      Solar powered pumping is technically feasible. However, solar energy intensity is variable and its collection requires high capital investment. Present production methods might require modification for most economic use of solar energy. Various irrigation and pumping practices are examined to determine those most compatible with use of solar power. The tentative conclusion of the study is that solar energy usage is most economical for driving pumps only during sunlight hours and where pumping requirements are uniform throughout the year. Solar energy is a more costly source of pumping power than electricity or natural gas.
    • The Prejudices, Polemics, and Politics of Water Management Versus the Reasonable Man Test

      Stribling, Barbara A. (Arizona-Nevada Academy of Science, 1976-05-01)
      American legislative bodies and juries of laymen are founded on the concept that what a reasonable man would do is what will be done. In actuality the synergistic effects of prejudice, politics, and polarized language rarely allow this to occur. The result has been conflict of interest statutorily mandated on natural resource governing boards and a lack of expertise in the courtroom. Further contempt has developed between citizen and expert and between legislator and bureaucrat. I propose to explore the operative mechanism in the situation and discuss possible future roles for both citizen and expert as well as tools which could be utilized by them.