• Effect of Urbanization on Runoff from Small Watersheds

      Kao, Samuel E.; Fogel, Martin M.; Resnick, Sol D.; Water Resources Research Center, The University of Arizona, Tucson, Arizona 85721 (Arizona-Nevada Academy of Science, 1973-05-05)
      Hydrologic data collected from three small urban watersheds and one rural watershed were analyzed for the purpose of investigating the effect of urbanization on runoff. A procedure developed by the Soil Conservation Service was used to explain the relationship between the amount of rainfall and runoff. It was noted that the runoff curve number, a parameter of the method, increased as the percentage of impervious area increased. Also, there was evidence that a linear relationship existed between the runoff volume and its corresponding peak rate.
    • 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.