An Analysis of the Influence of Variability Rainfall on Flow Rate Based on the Watershed Characteristics

Abstract

Flood is one of natural phenomena that often occurs during the rainy season. In general, flooding occurs due to the inability of the river to accommodate the discharge that enters into it. The rain that descends in a watershed will turn into a stream. Thus, there is a relationship between rainfall and flow rate (discharge), which depends on the geometric conditions of watershed. The aim of this research is to determine the amount of discharge that outflow from the watershed due to the rain that descends in the area. The process of transformation rainfall into discharge is done by using Nakayasu synthetic unit hydrograph method. Derivation of this method is done by using different rainfall input i.e. single station and rainfall watershed. The results unit hydrographs are then used for design flood calculation in river.