LUSI sediment characteristics and its distribution pathway in the porong river

Abstract

The Porong River has been utilized to remove mud from the Sidoarjo mud volcano through the spillway since September 2006. The existence of Sidoarjo Mud (LUSI) in the river adds to the source of sediment, resulting in high-capacity sediment transport and increased sediment concentration, affecting the ecosystem and river capacity. To determine sediment deposition around the LUSI outfall area, this study analyzed nine sections to obtain bed material data. Each section has three observation points to collect material samples to produce comprehensive data. The cross-section stretches from the LUSI outfall area downstream, with a cross-sectional distance of 1 km, so the total length is 9.5 km. The study found clear changes in sediment composition across the analyzed area, with sand dominating the sediment profile in the upper reaches of the LUSI outfall. Sand dominance is due to local scour on the bridge pillars and groundsills on the river bed. In addition, these muds show characteristic depositional pathways, concentrated mainly along the river banks. This study highlights the importance of understanding sediment dynamics, influenced by variations in sediment sources, in disaster management and mitigation.