Analysis of Flood Hydrograph Metro Sub Watershed with Synthetic Unit Hydrograph Snyder and SCS (Soil Conservation Service) Methods

Abstract

Metro Sub-watershed is in Malang City. Based on data from BPBD Malang City, flood disasters have continued to increase from 2016 - 2022. The purpose of this research is to analyse the synthetic unit hydrograph (SUH) which will be used as the basis for planning water resources management. The rainfall data used in 2012-2021 with an average maximum rainfall height of 108 mm... Metro sub-watershed with an area of 31.371 km2 and a river length of 42 km and land use data with 59% of the residential. All data will be analysed for SUH in return periods Q2 = 2th, Q5 = 5th, Q10 = 10th, Q25 = 25th, Q50 = 50th, and Q100 = 100th. SUH analysis using HEC-HMS auxiliary program with Snyder and SCS (Soil Conservation Service) methods. The peak discharge results of the SUH in the Snyder method are Q2 = 47.8 m3/s, Q5 = 48.6 m3/s, Q10 = 50.7 m3/s, Q25 = 52.8 m3/s, Q50 = 54.1 m3/s, Q100 = 55.2 m3/s, and in the SCS method are Q2 = 37.5 m3/s, Q5 = 37.9 m3/s, Q10 = 39.8 m3/s, Q25 = 41.8 m3/s, Q50 = 43 m3/s, Q100 = 44 m3/s.