• 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.
    • 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.