Estimation of peak discharge using a rational method in Kodil Sub-Watershed, Purworejo Regency, Central Java

Abstract

The Kodil Sub-Watershed is one of the areas that has a high potential for flooding in Bogowonto Watershed. Flood disasters can cause significant losses to society, both in terms of physical, social and economic. This causes are need for information on the estimated peak discharge in The Kodil Sub-Watershed. Peak discharge estimation uses the rational method and The Cook Method to measure runoff coefficient or C value. Runoff coefficient using The Cook Method uses physical parameters, i.e land use, slope, drainage density, and infiltration. These parameters are extracted using remote sensing technology and Geographic Information System (GIS). Remote sensing data used for extraction of physical land parameters of Sentinel 2A Imagery and DEM ALOS PALSAR imagery. The results of the processing of peak discharge by the method obtained an estimate of the peak discharge of the Kodil Sub-Watershed of 209,659 m3/second and an average peak discharge of 135,024 m3/second.