RUNOFF ESTIMATES FOR SMALL RURAL WATERSHEDS

THIS IS A FEASIBILITY STUDY FOR THE DEVELOPMENT OF A SOUND METHOD FOR ESTIMATING THE RUNOFF RATES OF ANY FREQUENCY UP TO A 50 YEAR RECURRENCE INTERVAL FOR ANY UNGAGED SMALL RURAL WATERSHEDS OF 20 SQUARE MILES OR LESS IN THE UNITED STATES. ABOUT 50 WATERSHEDS OF LESS THAN 25 SQUARE MILES IN PENNSYLVANIA AND OHIO WERE STUDIED WITH RESPECT OF THEIR FLOOD RESPONSE. A SIMPLE SINGLE-EVENT MODEL FOR FLOOD FREQUENCY ESTIMATES IS NOT FOUND TO BE FEASIBLE. SIX CURRENTLY AVAILABLE METHODS FOR MAKING RAPID ASSESSMENTS OF FLOOD PEAKS FROM VERY SMALL WATERSHEDS ARE DISCUSSED. THEIR RELATIVE PERFORMANCE IS EVALUATED IN COMPARISON TO FREQUENCY ANALYSES MADE ON OBSERVED ANNUAL FLOOD SERIES. A MODIFIED REGIONAL FLOOD FREQUENCY METHOD APPEARS TO BE SUPERIOR. IMPROVED WAYS OF BLENDING MAXIMUM SUPPORTING INFORMATION INTO SUCH A METHOD ARE DISCUSSED, WITH EXAMPLES FROM EASTERN UNITED STATES AND HIGH-ELEVATION ARIZONA FORESTED WATERSHEDS. THE IDEA OF A CHARACTERISTIC TEN SQUARE MILE FLOOD IS INTRODUCED AS AN AID TO DEMARCATING HYDROLOGIC REGIONS. /FHWA/ INTRODUCED AS AN AID TO DEMARCATING HYDROLOGIC REGIONS. /FHWA/

  • Corporate Authors:

    Pennsylvania State University, University Park

    Department of Civil and Environmental Engineering, Sackett Building
    University Park, PA  United States  16802

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Reich, B M
  • Publication Date: 1971-7

Media Info

  • Pagination: 226 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00204044
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Contract Numbers: DOT-FH-11-7429
  • Files: TRIS, USDOT
  • Created Date: Jul 29 2004 5:32PM