Abstract
On May 29, 2006, mud and gases began erupting unexpectedly from a hydrocarbon exploration well near Sidoarjo, Indonesia. The eruption has continued since then at rates as high as 180,000 m3 per day and the mud inundated an area in excess of 6.5 km2 and caused over 30,000 persons to be displaced. The mud is being pumped into the Porong River, which then carries the mud to the ocean approximately 26 km to the east. However, the accumulation of mud in the river might result in sedimentation through the riverbank and spreading across the fisheries' aquaculture area along the coast. The main objective of this study is to assess the effect of mudflows from the LUSI volcano on the river environment such as mud deposition in the Prong River using the observed river cross sections before and after the eruption of the volcano. From the analysis, it was found that a significant sediment deposition was occurred at the river bed of Porong River due to increased sediment discharge from the volcano during the dry periods, and then the sediment depositions in the river bed were gradually eroded and flushed away by floods and high water flows during the wet periods.
