Flood frequency analysis for Tel sub-basin of Mahanadi River, India using Weibull, Gringorten and L-moments formula
The objective of this study is to determine the magnitude and frequency of floods for Tel sub-basin of Mahanadi river system, India using Gumbel distribution. The probability plot and flood-frequency curves by Gumbel distribution of each individual station are prepared using three different plotting position formulas (i.e. Weibull, Gringorten and L-moments). From the results and analysis of two stations of Tel sub-basin, Gumbel distribution based on L-moments always gives the least ratio of peak discharge of T years recurrence interval over mean annual flood (QT/MAF), also the pertinence of L-moments with Gumbel distribution have some limitations and it is only good for small samples data. If compared between Gumbel distribution by Weibull formula and Gumbel distribution by Gringorten formula, the latter is better because it gives the least ratio (which is in agreement with the literature). Therefore, it could be concluded that for both the stations L-moments method is the best, but since L-moments method have some limitations, Gringorten formula is still the best plotting position method to be applied with Gumbel distribution.
Gringorten; Gumbel Distribution; L-moment; Weibull