Application of
Gumbel’s Distribution Method for Flood Frequency Analysis of Lower Ganga Basin (Farakka
Barrage Station), West Bengal, India
Mandal Kajal Kumar, Dharanirajan K. and Sarkar Sabyasachi
Disaster Advances; Vol. 14(8); 51-58;
doi: https://doi.org/10.25303/148da5121; (2021)
Abstract
The analysis of flood frequency will depend on the historical peak discharge data
for at least 10 years. This study has taken into account peak annual maximum discharge
data for 72 years (1949 to 2020). The discharge data was collected from the Farakka
Barrage Gauging station (24°48'15.10" N and 87°55'52.70" E) situated in the upper
part of lower Ganga basin. The flood frequency analysis of the lower Ganga basin’s
upper portions has been carried out using Gumbel’s frequency distribution method.
Gumbel’s method (XT) is a prediction analysing statistical approach. The discharge
data was tabulated in descending order and rank has been assigned based on the discharge
volume. The return period was calculated based on Weibull’s formula (P) for this
analysis. The flood frequency data was plotted on a graph where X-axis shows the
return period and the Yaxis is the discharge value. The R2 value of this graph is
0.9998 which describe Gumbel’s distribution method is best for the flood frequency
analysis. The flood frequency analysis is an essential step to assess the flood
hazard.
