SURFACE RUNOFF FROM AGRICULTURAL WATERSHEDS

PROBABILITY STUDIES INTEGRATE THE FREQUENCY OF OCCURRENCE OF VARIOUS WATERSHED CONDITIONS WITH THE FREQUENCY OF OCCURRENCE OF VARIOUS RAINFALL INTENSITIES AND PATTERNS AND ARE, THEREFORE, ESPECIALLY USEFUL IN ESTIMATING PEAK RATES OF RUNOFF FROM SMALL WATERSHEDS THAT MAY BE EXPECTED FOR VARIOUS RECURRENCE INTERVALS. THE THEORY OF EXTREME VALUES, DEVELOPED BY DR. E. J. GUMBEL, ASSUMES A DISTRIBUTION OF PEAK RATES SUCH THAT THE COEFFICIENT OF SKEW DOES NOT HAVE TO BE CALCULATED AS IS THE CASE WITH THE HAZEN AND FOSTER PROBABILITY CURVES. FOR THIS REASON THE GUMBEL CURVE IS VERY WELL SUITED FOR USE IN PROBABILITY STUDIES OF SKEWED DISTRIBUTIONS AS THOSE OF RAINFALL AND RUNOFF DATA. PROBABILITY STUDIES BASED ON SHORT-TERM RUNOFF RECORDS ARE RELIABLE ONLY IF THE RAINFALL FOR THE SHORT PERIOD IS A GOOD SAMPLE OF A MUCH LONGER PERIOD. THREE NORMALCY TESTS SHOULD BE APPLIED TO THE RAINFALL AND PROBABILITY CURVES SHOULD BE CORRECTED WHEN RAINFALL FOR THE PERIOD OF RUNOFF RECORD IS FOUND TO BE ABNORMAL. PROBABILITY STUDIES HAVE BEEN COMPLETED FOR SEVEN PHYSIOGRAPHIC AREAS AND THE RECOMMENDED PEAK RATES OF RUNOFF FOR USE IN THE DESIGN OF CONSERVATION STRUCTURES HAVE BEEN PUBLISHED IN TECHNICAL PUBLICATIONS OF THE SOIL CONSERVATION SERVICE. THESE RECOMMENDED PEAK RATES ARE SUMMARIZED FOR FIVE OF THE SEVEN AREAS. /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrbresearchrpts/1950/11B-003.pdf
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  Highway Research Board (HRB)

  Washington, DC   
• Authors:
  • Potter, W H
• Conference:
  • 29th Annual Conference of the Highway Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1949-12-0 to 1949-12-0
• Publication Date: 1950-12

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 15p
• Monograph Title: Surface drainage
• Serial:
  • Highway Research Board Research Reports
  • Issue Number: 11B
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Hydrology; Peak fares; Probability theory; Rainfall; Runoff; Watersheds
• Subject Areas: Data and Information Technology; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00204409
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: May 22 1972 12:00AM