The Estimation of Surface Run-off in Sub Watershed Kampili using the HEC-HMS Model Ayu, Mahmud Achmad, dan Iqbal
Universitas Hasanuddin
Abstract
The Kampili sub watershed is one of the areas quite prone because it is directly adjacent to the Jeneberang watershed, making it easier for river water to overflow. Changes in land use following population growth are one of the causes. In addition, it is also influenced by regional development patterns, which causes the flow of river flows to increase. The HEC-HMS (Hydrologic Engineering Center-Hydrologic Modeling System) model is a program that can provide hydrological simulations of the daily peak flow for the calculation of the planned flood discharge from a watershed. The purpose of this study is to determine the validity level of the HEC-HMS model in predicting flooding and to determine the amount of planned flood discharge that would occur during the 2, 5, 20 and 50 years return periods in the Kampili sub watershed. In the HEC-HMS modeling there are several are rainfall data, discharge data, land use data, and soil types in the Kampili sub watershed. There are three results obtained, namely calibration, validation and rain plan. In the calibration stage, the difference between the observed value and the model simulation value is obtained. At the validation stage, the Nash-Sutcliffe Efficiency (NSE) value method is used. The NSE value obtained is 0,589. Based on these data, the HEC-HMS is quite valid in predicting flood events in the Kampili sub-watershed. The planned rain for each return period of 2, 5, 20 and 50 years, the peak discharge is obtained respectively, namely 217,1 m3/s, 246,7 m3/s, 275,1 m3/s and 289,8 m3/s.
