RUNOFF ESTIMATES FOR SMALL RURAL WATERSHEDS AND DEVELOPMENT OF A SOUND DESIGN METHOD: VOLUME I-RESEARCH REPORT

Potter's method for runoff peak forecasting was examined on its original watersheds and it was found to be soundly conceived. The method was modified to extend it to other watersheds in the same States for which it was originially developed. The results after modifying Potter's C parameter were found to be satisfactory. The method was simplified and extended to all of the contiguous United States, Alaska, Hawaii, and Puerto Rico. After beginning with a 7-parameter method, it was found that 3-parameters, namely area, rainfall erosivity factor and difference in elevation from top to bottom of the watershed produced peak flow estimates of virtually equal reliability . The standard error of estimates of the ten year peak flow as computed by the different equations for a random sample of 51 water sheds from throughout the United States and Puerto Rico were: 39 percent for the 3-parameter all zone, 62 percent for 7-parameter all zone, 50 percent for 3-parameter zone, and 38 percent for 7-parameter zone equations. Consequently the three parameter equations were selected for design puposes and nomographs for solving the equations were developed for each hydrophysiographic zone of the United States and Puerto Rico. /FHWA/

  • Corporate Authors:

    Utah State University, Logan

    Utah Water Research Laboratory
    Logan, UT  USA  84321
  • Authors:
    • Fletcher, J E
    • Huber, A L
    • Haws, F W
    • Clyde, C G
  • Publication Date: 1977-10

Media Info

  • Pagination: 120 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00182546
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FHWA-RD-77-158 Final Rpt., FCP 35H3-012
  • Contract Numbers: DOT-FH-11-7809
  • Files: TRIS
  • Created Date: Dec 12 1978 12:00AM