Effects of mud flows from the LUSI mud volcano on the Porong River estuary, Indonesia

On May 29, 2006, mud and gases began erupting unexpectedly from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI (Lumpur Sidoarjo Lumpur means mud in Indonesian) mud volcano, has continued since then at rates as high as 180,000 m³ per day. The mud inundated an area in excess of 6.5 km², in spite of attempts to contain it via the construction of a series of levees. The mud is erupting and accumulating behind the levee system. It is also being pumped into the Porong River, which then carries the mud to the ocean approximately 20 km to the east. The main objective of this study is to assess the effect of mudflow from the LUSI volcano on the river and estuary environment such as sediment deposition and water quality using the observed river cross sections and bathymetry data after the eruption of the LUSI volcano. From the analysis it was found that a significant sediment deposition occurred at the river bed of Porong River due to increased sediment discharge from the volcano during the dry periods after which the sediment deposits on the river bed were gradually eroded and flushed away to the ocean by floods and high water flows during the wet periods. Environmental impacts due to increased sediment from the Porong River on the estuary and coastal region are discussed.