• Salt Balance in Groundwater of the Tulare Lake Basin, California

      Schmidt, Kenneth D. (Arizona-Nevada Academy of Science, 1975-04-12)
      The Tulare Lake basin at the base of the Sierra Nevada Mountains is the basis for water supply for several cities and a highly productive agricultural area. Little attention has been given to groundwater quality during the past one hundred years. A careful study of the salt balance produced a set of guidelines for future groundwater managers to follow. The major emphasis for future water consumption should be the efficient use of irrigation. This would produce a positive impact on groundwater quality, energy savings, and less imported water would be needed. Groundwater management in the future must consider water quality as well as quantity. Appropriate monitoring programs are urgently needed to provide data on trends in groundwater quality.
    • State Water Planning

      Steiner, Wesley E.; Arizona Water Commission, Phoenix, Arizona (Arizona-Nevada Academy of Science, 1975-04-12)
      From the establishment of the Arizona resources board in 1928 until the Arizona Water Commission was formed in 1971, no state water plan was developed. Since 1971, the longest and most intensive planning studies have been concerned with allocation of Colorado River water through the central Arizona project. Future plans involve desalting sea water, weather modification, importation of water, etc. The Arizona state water plan ultimately will be a plan of management of Arizona's limited water resources. Water plans and economic and environmental impact evaluations are scheduled for completion by july, 1977.
    • Thunderstorm Precipitation Effects on the Rainfall-Erosion Index of the Universal Soil Loss Equation

      Renard, Kenneth G.; Simanton, J. Roger; United States Department of Agriculture, Agricultural Research Service, Western Region, Southwest Watershed Research Center, Tucson, Arizona 85705 (Arizona-Nevada Academy of Science, 1975-04-12)
      The universal soil loss equation (USLE) is widely used for estimating annual and individual storm erosion from field-sized watersheds. Records from a single precipitation gage in climatic areas dominated by thunderstorms can be used to estimate the erosion index (EI) only for the point in question on individual storms or for a specific annual value. Extrapolating the results for more than about a mile leads to serious error in estimating the erosion by the use of the USLE. Short time intervals must be used to obtain an adequate estimate of the EI when using the USLE. The variability of the annual EI can be approximated with a log-normal distribution. All studies indicated that investigations are needed to facilitate estimating the average annual EI from precipitation data as reported by state climatological summaries for states west of the 104th meridian. Additional work is needed to facilitate estimating the EI value from the precipitation data available in most areas of the southwest where thunderstorms dominate the rainfall pattern.
    • Transformations in Quality of Recharging Effluent in the Santa Cruz River

      Wilson, L. G.; Herbert, R. A.; Ramsey, C. R.; Water Resources Research Center; Department of Soils, Water and Engineering, The University of Arizona, Tucson (Arizona-Nevada Academy of Science, 1975-04-12)
      Since 1955 secondary treated effluent from the city of Tucson treatment plant has been released into the Santa Cruz River, the principal drainage tributary of the Tucson basin. Because the river is ephemeral, it has functioned essentially as an artificial recharge facility for sewage effluent. In past years the total volume of effluent artificially recharged amounted to about 31,000 ac-ft per year. Such recharge has affected not only the groundwater levels in the vicinity of the river, but also water quality. Recharge of nitrate is of particular concern.
    • Variability of Infiltration Characteristics and Water Yield of a Semi Arid Catchment

      Nnaji, Soronadi; Sammis, Ted W.; Evans, Daniel D.; Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1975-04-12)
      Space-time variability in the hydrologic characteristics of four major soil series represented in the Silverbell validation site was investigated by sampling the infiltration characteristics, at randomly selected locations, under several vegetative covers within each series. The experimental data was the time distribution of infiltration which, for each sampled location, was fitted by least squares to the Philip's infiltration equation. The parameters of this equation have physical interpretation and therefore were used as measures of the infiltration characteristics. Analysis of variance was used to investigate the spatial variability in the parameters. The mean values of the parameters for selected soil-vegetation combinations were used to simulate runoff due to a rainfall event over a desert catchment "containing" the given combination. Statistical tests show that there is no significant difference among the infiltration parameters of all the soil-vegetation combinations. However, the statistically insignificant variations in the parameters produce significant variations in simulated runoff volumes indicating the sensitivity of the runoff generating process to infiltration characteristics vis-a-vis the hydrologic properties of the soils.
    • Water Resources of the Woody Mountain Well Field Area, Coconino County, Arizona

      Montgomery, Errol L.; DeWitt, Ronald H.; Northern Arizona University; City of Flagstaff Water Department (Arizona-Nevada Academy of Science, 1975-04-12)
      Conclusions drawn from a water resources study of the woody mountain area are: the average coefficients of transmissibility and of storage of the principal aquifer are approximately 30,000 gpd/ft and 0.05 respectively; drawdown in wells is greater than predicted using theoretical calculations due to the turbulent flow near the well bore in the fractured Coconino aquifer; the computed interference between pumped wells in the field ranges from 10.5 ft. To 19.7 ft. Interference would be negligible between wells spaced at distances greater than 6,000 ft. For pumping periods as long as two hundred days; the negative boundary effect of off-set on the oak creek fault may be balanced by the recharge effect of groundwater located in the highly permeable fractured zone adjacent to the fault; and the quantity of recharge water to the well field is greater than withdrawals from the wells.
    • Watershed Indicators of Landform Development

      Heede, Burchard H.; Arizona State University, Tempe, Arizona; Colorado State University, Fort Collins (Arizona-Nevada Academy of Science, 1975-04-12)
      Traditionally, watershed management is concerned with water and sediment yield, vegetation, soils, and meteorology, but not with geomorphology. Often it is in this field that the explanation can be found for the formation and present condition of a watershed and its future development. Examples are presented to demonstrate that factors in the hydraulic geometry of streams indicate whether a watershed is in an active stage of landform development, or is in dynamic equilibrium. Some general guides for the practitioner are provided. Watershed management research cannot afford to ignore the basic geomorphic setting of watersheds. If geomorphology is not considered, the researcher's results could be misinterpreted.