COMPARATIVE EVALUATION OF FOUR REGIONAL FLOOD-FREQUENCY ANALYSIS METHODS

Four popular methods for analyzing regional flood frequency were investigated using Louisiana streamflow series. The state was divided into four homogeneous regions and all undistorted, long-term stream gauges were used in the analysis. The generalized extreme value (GEV), two-component extreme value, and regional log Pearson Type III methods were applied to this data base and compared in terms of descriptive capabilities. On the basis of several factors, the GEV method was selected as the overall superior method. The GEV parameters were estimated using the probability-weighted moments (PWMs). Indexing was accomplished using the first PWM (the mean). A procedure to apply this method to ungauged watersheds using regression equations and a regional nondimensional flood distribution was developed. It was found that the procedure performed well when applied to data not used in the calibration of the model. The regional GEV procedure was compared with the method of the U.S. Geological Survey (USGS) and showed significant improvement over the USGS equations in terms of fit to the observed data. This method is easier to apply and more accurate in terms of descriptive and probably predictive ability than other feasible methods for Louisiana data.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 1-7
  • Monograph Title: Hydrology and bridge scour
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00625180
  • Record Type: Publication
  • ISBN: 0309052149
  • Files: TRIS, TRB
  • Created Date: Oct 22 1993 12:00AM