Now showing items 21-36 of 36

    • Aspects of Aquifer Test Error Analysis

      Benbarka, Ahmed M.; Davis, Donald R.; Department of Hydrology and Water Resources, University of Arizona (Arizona-Nevada Academy of Science, 1981-05-02)
      Errors in the estimation of the aquifer parameters T and S derived from aquifer test data are examined as to their cause and effects. The analysis is based on the Theis equation. The basic causes of error are in the measurements of drawdown and pumping rate, in fitting the model to the data and in violations of model assumptions. Measurement errors were studied experimentally. Curve fittings by hydrologists were compared to "automatic" curve fittings obtained by nonlinear regression. The covariance matrix of T and S obtained in this manner was used, in conjunction with sensitivity analysis, to estimate the error in prediction of future drawdown. While automatic fitting is not a perfect substitute for graphical fitting, there is a definite relation between the two methods which allows the use of the statistics developed by nonlinear regression theory to be used to study the cause, effects and risks inherent in aquifer analysis.
    • Correcting Tidal Responses in Observed Water Well Levels During Coastal Aquifer Tests

      Popkin, Barney P.; Dames & Moore, Houston, Texas 77092; Environmental Research Laboratory, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1981-05-02)
      A modified tidal efficiency algorithm, ESTA, was developed to correct observed water well levels in tidally responsive coastal areas to get best estimates of aquifer properties and well production characteristics. The algorithm was developed during groundwater studies in Puerto Peñasco, northeastern Gulf of California, Sonora, Mexico. ESTA predicts standing water well levels in response to tides. ESTA requires initial sea and well calibration data, from which sea-well relationships are calculated. It needs tidal data for the time period when projected standing water well levels are desired. The method uses a single cosine or sine function for rising or falling tides, respectively. ESTA tended to overpredict water levels, especially on rising tides, on the average of about 0.05 ft, as shown in analyses at five coastal well sites completed in low to moderately permeable sand and coquina. ESTA can be improved by application of error analysis, but this will not be necessary in most cases, as errors are generally very small for most aquifers and tidal ranges. When ESTA was applied to an aquifer test in highly permeable coral near Kahuku, northehore Oahu, Hawaii, rising -tide water well levels were overpredicted and falling -tide water well levels were underpredicted by 0.10 and 0.33 ft, respectively. Error analysis reduced these errors to 0.06 and 0.16 ft.
    • Some Effects of Controlled Burning on Surface Water Quality

      Sims, Bruce D.; Lehman, Gordon S.; Ffolliott, Peter F.; School of Renewable Natural Resources, University of Arizona (Arizona-Nevada Academy of Science, 1981-05-02)
    • Arizona Solar Powered Pumping Project: Operating Experiences

      Larson, Dennis L.; Soils, Water and Engineering Department, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Energy Budget Measurements Over Irrigated Alfalfa

      Gay, L. W.; Hartman, R. K.; School of Renewable Natural Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Estimating Potential Evapotranspiration in Arid Environments

      Osmolski, Z.; Gay, L. W.; School of Renewable Natural Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Evaluation of the Use of Soil Conservation Service Snow Course Data in Describing Local Snow Conditions in Arizona Forests

      Gottfried, Gerald J.; Ffolliott, Peter F.; USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, Arizona State University, Tempe, Arizona 85281; School of Renewable Natural Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Use of the Universal Soil Loss Equation in the Tropics

      Rasmussen, Todd C.; Tracy, Fred C.; Department of Hydrology and School of Renewable Natural Resources, University of Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • An Analysis of Recession Flows from Different Vegetation Types

      Sulaiman, Wan Norazmin bin; Ffolliott, Peter F.; School of Renewable Natural Resources, University of Arizona (Arizona-Nevada Academy of Science, 1981-05-02)
    • Point-Area-Frequency Conversions for Summer Rainfall in Southeastern Arizona

      Osborn, Herbert B.; Lane, Leonard J. (Arizona-Nevada Academy of Science, 1981-05-02)
    • Stormflow as a Function of Watershed Impervious Area

      Pankey, Jan M.; Hawkins, Richard H.; Tonto National Forest, Phoenix, Arizona 85038; College of Natural Resources, Utah State University, Logan, Utah 84322 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Candelilla/Petroleum Wax Mixtures for Treating Soils for water Harvesting

      Fink, Dwayne H.; U. S. Department of Agriculture, Science and Education Administration, U. S. Water Conservation Laboratory, Phoenix, AZ 85040 (Arizona-Nevada Academy of Science, 1981-05-02)
      A vegetable wax (candelilla), alone or in combination with petroleum waxes, was evaluated for treating soils for water harvesting. Samples were alternately weathered in a freeze -thaw cycle chamber, tested for water repellency and structural stability against water erosion, then subjected to more weathering, etc., until sample failure occurred. Soils treated with candelilla/paraffin wax mixtures were much more resistant to laboratory freeze -thaw cycle weathering than those soils treated with either of the waxes alone. Weatherability was further improved, and wax requirement reduced by (1) prior stabilization of the soil with cellulose xanthate made from chemically pulped waste paper; (2) incorporating 28 of a commercial antistripping agent into the wax; and (3) substituting a residual type petroleum wax for the paraffin in the wax mixtures.
    • Water Yield Opportunities on National Forest Lands in Arizona

      Solomon, Rhey M.; Schmidt, Larry J.; USDA Forest Service, Albuquerque, New Mexico (Arizona-Nevada Academy of Science, 1981-05-02)
      Water Yield improvement opportunities were estimated for National Forest lands in Arizona. The land base available for treatment was reduced in a stepwise manner to account for administrative, climatic, and ownership constraints. Research relationships were built upon, and then applied to the remaining land base to project water yield estimates. A continuum of management prescriptions was then displayed to show the range of opportunities. Only the chaparral, ponderosa pine, and mixed conifer types show opportunities of significance. Water yield increases can be realized principally from conversion of chaparral to grass and could add an additional 25 to 70 thousand acre-feet. The ponderosa pine zone could add an additional 15 to 30 thousand acre-feet with intensive management by reducing stocking levels on the commercial National Forest lands. Little opportunity exists within the mixed conifer zone and increases would amount to less than 10 thousand acre -feet. Annual contributions of National Forest lands are likely to range from 40 thousand to 100 thousand acre feet; this will be highly variable depending upon precipitation quantities.
    • Sediment Sources of Midwestern Surface Waters

      Wilkin, Donovan C.; Hebel, Susan J.; School of Renewable Natural Resources, University of Arizona; Department of Landscape Architecture, University of Illinois (Arizona-Nevada Academy of Science, 1981-05-02)
    • Hydrologic Regimes of Three Vegetations Types Across the Mogollon Rim

      Baker, Malchus B., Jr.; Rocky Mountain Forest and Range Experiment Station. Flagstaff, Arizona 85721 (Arizona-Nevada Academy of Science, 1981-05-02)
    • Relationships of Soil Texture with Soil water Content and Soil Porosity Characteristics of Arizona Soils

      Post, Donald F.; Department of Soils, Water and Engineering, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1981-05-02)