• 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.
    • 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.