EFFECTIVENESS OF SABO DAM IN INTEGRATED FLOOD CONTROL IN THE MILANGODAA RIVER.

• Main Author: Irmanto
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/78565
• Institution: Institut Teknologi Bandung

This study aims to evaluate the effectiveness of using sediment control structures, such as a sabo dam, in reducing flood risks and controlling sedimentation in the Milangodaa River after experiencing a flood disaster in August. Using hydrological and topographic data, this research seeks to provide in-depth insights into the positive impacts and potential solutions for reducing natural disaster risks and protecting the river environment. Hydrological analysis was carried out using the HEC-HMS program, with initial topographic analysis using GIS applications. Hydraulic analysis was performed using HEC-RAS 6.3.1 to analyze floods, aggradation, and degradation of the riverbed. The river's geometry used in this study was based on measurements from 2020. Based on sediment transport simulations with low flow rates over 2 years under existing conditions, the Left River experienced degradation of 126.406 m3/2 years, the Right River experienced 11.362 m3/2 years, and the Downstream River experienced 43.939 m3/2 years. Under the Sabo Dam model conditions, the Right River experienced degradation of 60.019 m3/2year, the Left River experienced aggradation of 2.923 m3/2 years, and the Downstream River experienced 143.934 m3/2 years. In flood simulations under existing river conditions in the downstream area, there was overflow at the Q25 discharge with a water surface elevation at STA 1450 of 23.33 meters, and with the river's model geometry, it became 23.04 meters. Based on these results, it can be concluded that the construction of a Sabo Dam causes degradation downstream, thereby increasing the river's capacity to accommodate water. For flood control, river improvement or normalization is more effective than using a Sabo Dam. Sabo dams are designed primarily to control sediment and reduce the velocity or energy of floodwaters.