Application of Rational Formula to Estimate Peak Flood for a Partially Urbanized Catchment

Abstract

The Rational Formula (RF) stands out as a widely utilized equation in applied hydrology for calculating peak discharge. Its prevalence is attributed to its simplicity and adept balance between theoretical principles and the accessibility of data in practical applications. The current studies address the application of RF on an ungauged partially urbanized catchment. Certain parameters e.g. catchment area, drainage network, soil information, land use land cover was extracted through application of GIS tools.   The intensity–duration–frequency rainfall curves and time of concentration Tc were estimated for the study area. Finally, the Gumbel distribution was applied for the intensity duration frequency analysis. The intensities varied from 86.55mm/hr to 98.79mm/hr for a station for 25-years & 50-years return periods which produces the peak floods of 291.24m3/s & 332.41m3/s respectively.
KEYWORDS: Rational Formula, Peak Discharge, Urbanized Catchment