ANALYSIS OF SEDIMENT CHARACTERISTICS AND FLOW DYNAMICS AFTER NORMALIZATION OF THE CITARUM-MAJALAYA RIVER IN INDONESIA

Abstract

The Citarum-Majalaya River is frequently inundated by annual flooding. The floods carry sediment material and sedimentation up to 25 cm in some locations. Structural efforts to maintain river capacity have been made by normalizing the river in 2021, but significant flooding occurred again in 2023. This study analyzes sediment transport dynamics in the Citarum-Majalaya River. Data collection includes secondary data from previous erosion and sedimentation studies in the watershed. The primary data was obtained by direct measurement in the upstream and downstream under two water level conditions. The findings of data analysis and laboratory testing indicate that the type of flow in the Citarum-Majalaya River section is turbulent and subcritical, and the type of sediment is sand and clay, with distinct sediment movement patterns between upstream and downstream. The turbulent and subcritical flow allows particles to remain suspended for longer periods and settle more rapidly when the flow decreases, predicting high sedimentation levels in this river and reducing the river's capacity.