APPLICATION OF STANFORD WATERSHED MODEL CONCEPTS TO PREDICT FLOOD PEAKS FOR SMALL DRAINAGE AREAS

THE DETERMINATION OF A DESIGN DISCHARGE IS A MAJOR PROBLEM IN THE DESIGN OF DRAINAGE STRUCTURES FOR SMALL BASINS. APPROXIMATELY 15% OF THE EXPENDITURES FOR HIGHWAY CONSTRUCTION GO TOWARD DRAINAGE FACILITIES FOR SMALL BASINS. THE COSTS OF THESE STRUCTURES PLUS MAINTENANCE AND CONSTRUCTION COSTS WHICH ARE CONTINUALLY INCREASING, SUGGEST THAT CARE SHOULD BE EXERCISED IN DETERMINING DESIGN DISCHARGES IN ORDER TO MINIMIZE OVERDESIGN OF DRAINAGE STRUCTURES. A PROCEDURE IS REPORTED WHICH WAS ESTABLISHED FOR RELATING FLOOD PEAKS TO MEASURABLE WATERSHED CHARACTERISTICS. IT IS BASED ON DATA FROM THE CAVE CREEK WATERSHED AS ANALYZED BY THE STANFORD WATERSHED MODEL. A METHOD WAS FORMULATED FOR ESTIMATING RUNOFF COEFFICIENTS FOR VARIOUS BASINS WHEN THEIR WATERSHED CHARACTERISTICS ARE KNOWN. RUNOFF COEFFICIENTS ARE QUITE SENSITIVE TO VARIATIONS IN WATERSHED CHARACTERISTICS AND CLIMATIC CONDITIONS, AND THE DEVELOPMENT OF A GENERALIZED RELATIONSHIP REQUIRES ANALYSIS OF A MULTIPLICITY OF INTERACTIONS. THIS REQUIREMENT WAS SATISFIED THROUGH THE DIGITAL COMPUTER AND THE STANFORD WATERSHED MODEL. CURVES PRESENTED WERE DEVELOPED FOR AN AREA HAVING A MEAN ANNUAL RAINFALL OF APPROXIMATELY 40 INCHES, WHICH IS RATHER EVENLY DISTRIBUTED THROUGHOUT THE YEAR. FLOOD PEAKS LOWER THAN ACTUAL MIGHT RESULT IN APPLICATION OF THE METHOD TO AREAS MORE HUMID. THE METHOD IS BASED UPON DATA FOR A BASIN WHICH IS DRAINED BY NATURAL CHANNELS HAVING A CAPACITY APPROXIMATELY EQUAL TO THE MAIN ANNUAL FLOOD. ADDITIONAL STUDIES ARE RECOMMENDED TO DEFINE THE TIME-OF-CONCENTRATION, THE EFFECTS OF BASIN SIZE AND URBANIZATION EFFECTS.

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Filing Info

  • Accession Number: 00204186
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Feb 24 1994 12:00AM