• Competitive Groundwater Usage from the Navajo Sandstone

      Doye, F. H.; Roefs, T. G.; University of Arizona, Department of Hydrology and Water Resources (Arizona-Nevada Academy of Science, 1973-05-05)
      Groundwater modeling is used to theoretically relate mining pumpage of the Navajo Sandstone to declines in the potentiometric surface at Navajo and Hopi Indian community, domestic, and stock usage locations. The shallow wells on top of Black Mesa are shown to be part of a perched water table condition which is dependent upon the hydraulic conductivity of an aquatard known as the Mancos Shale. The isolation of the aquatard allows the shallow wells to be treated as a problem separate from that of the artesian and recharge areas. Computer modeling of the groundwater system is concerned only with those Indian wells which directly tap the Navajo Sandstone in either artesian or free water table areas. The computer simulation developed is a modified version of the basic artesian aquifer routine used by the Illinois State Water Survey. Computer results correspond with the low percentage of storage withdrawal calculated for the artesian area under Black Mesa.
    • Effects of a Wetting Agent on the Infiltration Characteristics of a Ponderosa Pine Soil

      Kaplan, Marc G.; Zwolinski, Malcolm J.; Department of Watershed Management, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1973-05-05)
      An infiltration- wetting agent study, using the wetting agent "WATER-IN", was conducted in the ponderosa pine forest type of east central Arizona. An application rate of 10 gallons of wetting agent per acre was used on bare mineral soil and on ponderosa pine litter. The infiltration rate was measured by a modified North Fork infiltrometer. It was found that "WATER-IN" significantly increased water runoff when applied to litter, but, when applied to bare mineral soil, "WATER-IN" caused a significant increase in water infiltration. The wetting agent did not significantly affect antecedent moisture, soil particle distribution, litter water holding capacity, or litter bulk density. It is presently hypothesized that the increase in water infiltration on treated bare mineral soil is due to a decrease in the average bulk density of the surface inch of soil. The increase in runoff when litter is treated is probably due to an interaction, either physical, chemical, or both, between the humus layer and "WATER-IN ", creating a hydrophobic condition where one did not exist before.
    • Groundwater Geology of Fort Valley, Coconino County, Arizona

      DeWitt, Ronald H. (Arizona-Nevada Academy of Science, 1973-05-05)
      All groundwater in fort valley is presently found in perched aquifers. The regional water table in the area is estimated to lie at a depth of approximately 1750 feet. Groundwater reservoirs are perched on impermeable clay zones located at the base of alluvial units. Groundwater is also found in highly fractured volcanic zones overlaying impermeable clay zones. Perched aquifers also occur in interflow zones above either impermeable clays or unfractured volcanics. Groundwater in fort valley is the result of infiltration or runoff and from precipitation. This recharge water infiltrates the alluvium or fractured volcanic rocks until an impermeable zone is reached where it becomes perched groundwater. Greatest well yields come from these recharge aquifers; their reliability is largely dependent on precipitation and runoff. Most wells in the fort valley area supply adequate amounts of water for domestic use.
    • Groundwater Recharge from a Portion of the Santa Catalina Mountains

      Belan, R. A.; Matlock, W. G.; Soils, Water and Engineering Department, The University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1973-05-05)
      The geohydrology of a portion of the Santa Catalina Mountains including the definition of aquifer systems in the foothills was studied in order to calculate groundwater recharge to the Tucson basin. This underlying groundwater aquifer is the only source of Tucson, Arizona's water supply. A well network, well logs, geologic profiles, and a water level contour map were used as source information. Recharge was found to occur in some sections of washes and close to the mountains where washes cross or coincide with faults. Significant recharge to sand and gravel aquifers occurs directly through faults and joints. Little of the surface runoff is thought to recharge local aquifers because of low permeability layers beneath the alluvium and the short duration of the flows. Recharge calculation using the Darcy equation was subject to considerable error; but flow net analysis showed the total recharge to be 336 acre-feet per year representing about 50 acre feet per mile of mountain front per year.
    • A Jeep-Mounted Rainfall Simulating Infiltrometer

      Henkle, William R.; Northern Arizona University (Arizona-Nevada Academy of Science, 1973-05-05)
      An infiltrometer was designed to more closely simulate natural storm characteristics and still maintain sufficient portability to be used in various test sites in the field. In addition to portability, a relatively large test plot can be used over a relatively long duration. The instrument is designed to produce rainfall intensities of 2 to 6 inches per hour which are comparable to natural storm intensities found in northern Arizona. Capillary tubes produce water drops of equivalent kinetic energy at impact to natural raindrops. Errors due to lateral flow are minimized through peripheral wetting. Mounting the infiltrometer on a four-wheel drive vehicle allows nearly the portability of a hand carried unit with a greater water carrying capacity and allows the equipment to be large enough to test a representative plot.
    • Lake Powell Research Project: Hydrologic Research

      Jacoby, Gordon C.; University of California at Los Angeles (Arizona-Nevada Academy of Science, 1973-05-05)
      The Lake Powell Research Project is investigating the effects of man's activities on the Southeastern Utah-Northeastern Arizona region. A major portion of this project is devoted to the hydrology of Lake Powell, the largest recent modification in the region. This hydrologic research is separated into the following subprojects and administrative institutions: Subprojects: Streamflow Trends, Evaporation, Bank Storage / Institution: University of California at Los Angeles. Subprojects: Sedimentation, Physical Limnology, Lake Geochemistry / Institution: Dartmouth College. The project is now concluding its first year of full-scale research effort. The UCLA subprojects are aimed at developing an overall water budget for the lake, both on an annual and long -term basis. The Streamflow_trends study indicates that the Upper Colorado River Basin (UCRB) has shifted from a few extraordinarily wet decades in the early 1900's to several relatively dry decades up to the present. Evaporation efforts so far are toward installing a data collection system capable of furnishing data for mass-transfer and energy-budget calculations. The bank-storage study indicates that bank storage constitutes a large fraction of the impounded waters. Secondary as well as primary permeability may be of major importance in bank storage. The Evaporation and Bank Storage subprojects are working in close coordination with the Bureau of Reclamation. The Sedimentation subproject has shown that the rate may be in general agreement with earlier estimates from river flow and suspended sediment data. However, the distribution is affected by sediment dams formed by slumping of canyon wall material. Physical limnology studies indicate the presence of stratifications resulting from thermal and turbidity layers causing complex movements within the lake waters. Field and laboratory efforts in lake geochemical analyses indicate that the precipitation of calcium carbonate may be the most important chemical process in changing the water quality of the lake.
    • Penetrability and Hydraulic Conductivity of Dilute Sulfuric Acid Solutions in Selected Arizona Soils

      Miyamoto, S.; Ryan, J.; Bohn, H. L.; Department of Soils, Water and Engineering, College of Agriculture, The University of Arizona, Tucson 85721 (Arizona-Nevada Academy of Science, 1973-05-05)
      Measurements of penetrability and hydraulic conductivity in calcareous soils treated with a dilute sulfuric acid solution showed a severe decrease in conductivity with increasing concentrations over 1000 ppm. A slight decrease in penetrability was observed. Carbon dioxide evolution appeared to be responsible for flow reduction and temporary cessation at 10,000 ppm and 20,000 ppm. In sodic soils penetrability and conductivity increased markedly with sulfuric acid concentrations between 1,000 and 10,000 ppm. For a neutral soil, penetrability decreased with increasing sulfuric acid concentrations, and the stable conductivity for 500 to 5,000 ppm was higher than for water alone. The findings suggest that disposal of sulfuric acid concentrations greater than 1,000 ppm will result in plugging by carbon dioxide. In sodic soils the possibility exists of using sulfuric acid solutions for reclaiming salt and sodium-affected soils.
    • A Preliminary Assessment of Snowfall Interception in Arizona Ponderosa Pine Forest

      Tennyson, Larry C.; Ffolliott, Peter F.; Thorud, David S.; Department of Watershed Management, University of Arizona, Tucson 85721 (Arizona-Nevada Academy of Science, 1973-05-05)
      A preliminary assessment and ranking of the relative significance of five processes that may contribute to snow removal from ponderosa pine forest canopies was made, including wind erosion of canopy snow, snowslide from the canopy, stemflow, vapor transport from melt water, and vapor transport of canopy snow. The first three represent delayed delivery rather than net water loss. A snow load index was obtained through use of time lapse photography of the study site canopy, while incoming solar radiation and atmospheric processes were monitored. The snow load index was expressed as a ratio of forest canopy area covered with snow to the total canopy area. Results obtained over a 4-day period following a six-hour snowstorm showed that snow removal by snowslide and wind erosion was of significant importance, while vapor transport of melt water and canopy snow, stemflow, and dripping of melt water was of comparatively minor importance.
    • Probability Distributions of Snow Course Data for Central Arizona

      Carv, Lawrence E.; Beschta, Robert L.; Department of Watershed Management, University of Arizona, Tucson 85721 (Arizona-Nevada Academy of Science, 1973-05-05)
      A preliminary study of probability distributions for use on snowpack accumulation in the central Arizona highlands was made from 22 snow courses selected as having 10 or more years of available records. Due to the frequent occurrence of zero water equivalent value, application of a single continuous probability distribution is precluded. By means of two distributions, however, the snowpack water equivalent can be assessed by a binomial distribution describing the probability of snow, and a lognormal distribution describing the probability of water equivalent. The area chosen for detailed analysis is where the headwaters of many of Arizona's major river systems occur.
    • Salinity Problems of the Safford Valley: An Interdisciplinary Analysis

      Muller, Anthony B.; Department of Hydrology and Water Resources, University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1973-05-05)
      A change in groundwater quality, averaging approximately +0.13 millimhos electrical conductivity and +35 ppm chloride per year, has been documented between 1940 and 1972 with data from ten long -term sample wells. The decrement in the water quality of the surficial aquifer seems to be attributable to four major mechanisms. An increase in salinity may be expected from leakage of saline water from the artesian aquifer. Such leakage would be stimulated by pumping- caused reduction of confining pressure, and by the puncture of the cap beds by deep wells. Water reaching the aquifer from natural recharge may contribute salts to the system. Such recharging water, if passed through soluble beds, could contribute to the salt. Lateral movement of water through similar deposits may be a contribution, and the concentration and infiltration of agricultural water could also add to aquifer salinity. The economic analysis of the Safford Valley, based on the modeling of a "Representative Farm" analog, indicates that cotton will remain economical to produce on the basis of the projected salinity trends, for a significant time beyond limits of prediction. The analysis indicates that the optimum salt-resistant crops for the area are being cultivated, and, of these, alfalfa will cease to be productive in large areas of the valley by 1990. The entire valley will not produce alfalfa for profit by 2040. The methodologies shown in the paper indicate how pumping influences salinity change and outline salinity control recommendations for the area.
    • Use of Stock Ponds for Hydrologic Research on Southwest Rangelands

      Simanton, J. R.; Osborn, H. B.; USDA, ARS Soil, Water, and Air Sciences; Southwest Rangeland Watershed Research Center, Tucson, Arizona (Arizona-Nevada Academy of Science, 1973-05-05)
      Five livestock watering ponds on the walnut gulch experimental watershed were instrumented to evaluate the use of these ponds as a method for comparing rainfall amounts with runoff sediment volumes. Pond drainage area, vegetative cover, soil type, percent slope, and years of record were tested. Instrumentation consisted of water level recorders, and a topographic survey of each stock pond to ascertain its storage capacity. The results to date have been insufficient to reach definite conclusions due to instrumentation and surveying problems, and because of the natural variability of thunderstorm rainfall. Since most of these problems have now been corrected, future data should yield valuable hydrologic data for semiarid rangelands by means of these instrumented stock ponds.