RUNOFF ESTIMATES FOR SMALL RURAL WATERSHEDS AND DEVELOPMENT OF A SOUND DESIGN METHOD: VOLUME II--RECOMMENDATIONS FOR PREPARING DESIGN MANUALS AND APPENDICES B, C, D, E, F, G, & H

Frequency analyses of more than 1,000 small watersheds in the United States and Puerto Rico were used to develop the estimation method for design of peak flow for ungaged watersheds. This method, called the Federal Highway Administration (FHWA) method, is conceptually similar to the Bureau of Public Roads (BRP) method developed by W.D. Potter. The FHWA method relates the runoff peak to easily determined hydrophysiographic parameters and is intended for use on watersheds smaller than 50 square miles. The concept test locations near Lexington, Kentucky. Pairs of test is the probability that one or more events will exceed a specified peak flow within the usable lifetime of the drainage structure. The return period of the design flood peak can then be modified according to the risk the designer is willing to take. Another concept dealing with the probable maximum runoff peak derived as a function of watershed area is included. The flow obtained from this relationship is considered to the the upper limit of the design flow that may realistically be expected to ever occur. As such it may be appropriate to use in situations where the consequences of failure are extremely great. /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: 368 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00182547
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-RD-77-159 Final Rpt., FCP 35H3-012
  • Contract Numbers: DOT-FH-11-7809
  • Files: TRIS, USDOT
  • Created Date: Dec 12 1978 12:00AM