A METHOD OF FINDING THE FAMILY OF RUNHYDROGRAPHS FOR GIVEN RETURN PERIODS

Most observed flood hydrographs at a problem point are composite hydrographs. Exponential functions describe both the rising and recession limbs of averaged composite hydrographs very well. These averaged composite hydrographs are called runhydrographs because run-theory was used in the averaging process. A log transformation results in triangular shapes for runhydrographs. Runhydrographs are therefore fully defined in terms of times-to-peak and peak rates of runoff measured on and from a selected horizontal truncation level, respectively. A bivariate lognormal probability distribution for times-to-peak and peak rates of runoff is a satisfactory descriptor for the occurrence of runhydrogrphs. Parameters were estimated from 50 years of continuous instantaneous hydrograph record for the Vaal River at Standerton. Contours of equal probability of exceedance were calculated from the bivariate log-normal probability distribution which enables the extraction of a family of runhydrographs for any desired probability of exceedance. This capability enables the civil engineers to select the members of this family of most interest to his flood problem. /Author/

  • Corporate Authors:

    Elsevier Science

    Radarweg 29, P.O. Box 211
    1043NX AE Amsterdam,   Netherlands 
  • Authors:
    • Hiemstra, LAV
    • Zucchini, W S
    • Pegram, GGS
  • Publication Date: 1976-5

Media Info

  • Features: Figures; References;
  • Pagination: p. 95-103
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00158173
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 28 1977 12:00AM