Hydrological modelling of Air Bengkulu river watershed in Indonesia using SUH and HEC-HMS models

Abstract

The purpose of this research is to develop a synthetic unit hydrograph model to determine the most suitable model for predicting peak discharge in the Air Bengkulu Watershed. Rainfall data were obtained from the Bengkulu Province Meteorology, Climatology, Geophysics Agency, from 2000 to 2019 year. The Synthetic Unit Hydrograph (SUH) method used to estimate the discharge in the Air Bengkulu River Watershed is the synthetic unit hydrograph, namely Snyder, ITB-1 and ITB-2, in addition to that also used HEC-HMS software. The estimation results of peak discharge and peak time for each type of hydrograph in the Air Bengkulu watershed are: Peak Discharge of Snyder 1,302.76 m3 / s with Peak Time 6,596 hours, Peak Discharge of ITB-1 2,395.50 m3 / s with Peak Time of 4,705 hours, Peak Discharge of ITB-2 2,165.857 m3 / s with Peak Time of 6,341 hours. It can be concluded that the synthetic unit hydrograph has been able to estimate the peak discharge based on the time sequence of a rain event, so there is a relationship between peak time and peak discharge. The peak and peak times obtained from the output of each method are different, so more in-depth research is needed if this model is to be used as a basis for decision making.