Regional Flood Formulas for Seven Subzones of Zone 3 of India

Abstract

Regional flood frequency curves are developed by fitting the L-moment based generalized extreme value distribution to annual maximum peak flood data of small-to-medium size catchments of the seven hydrometeorological subzones of Zone 3 and combined Zone 3 of India. These seven subzones cover an area of about 1,041,661 km2. Relationships developed between mean annual peak flood and catchment area are coupled with the respective regional flood frequency curves for derivation of the regional flood formulas. The regional flood frequency curves developed for each subzone together with at-site mean annual peak floods may be used for gauged catchments, whereas for ungauged catchments, regional flood formulas developed for the respective subzones may be adopted for obtaining rational flood frequency estimates.