RAINFALL INTENSITY-DURATION-FREQUENCY CURVES DEVELOPED FROM (NOT BY) COMPUTER OUTPUT

Thirty-two years of maxima observed at Tucson International Airport from the National Oceanic and Atmospheric Administration's recording raingage are used to prepare a sheet of intensity-duration-frequency curves commonly used in the design of storm drainage for small urban areas. The example is employed to stress the need for examining computer printouts of mathematical statistical analysis of the rains and their logarithms by plotting data on four types of probability paper. Stress is laid on dangers of blindly extrapolating a mathematical distribution that does not fit recorded amounts for the long return periods in which engineers are usually interested. Misapplication of scales involving a logarithmic transformation are discussed. The fact that longer durations may require a different type of frequency paper than do shorter durations is illustrated and rationalized on the basis of the physical process. Internal compatibility of results for 2-, 5-, 10-, 50-, and 100-year estimates of 5-, 10-, 20-, 30-, 45-, 60-, 120-, and 180-min rainfalls is preserved when examining a tabular array of as many as five frequency analyses on one of these 48 cells. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 35-43
  • Monograph Title: Geometrics, hydraulics, and hydrology
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00196765
  • Record Type: Publication
  • ISBN: 0309028302
  • Files: TRIS, TRB
  • Created Date: Sep 15 1979 12:00AM