The Great avulsion of Kosi on 18 August 2008

Abstract

The 18 August 2008 avulsion of the Kosi River draining the parts of north Bihar in eastern India may well be regarded as one of the greatest avulsions in a large river in recent years. The Kosi River shifted by ~120 km eastward, triggered by the breach of the eastern afflux bund at Kusaha in Nepal at a location 12 km upstream of the Kosi barrage. This event was widely perceived as a major flood in the media and scientific circles. Although a large area was indeed inundated after this event, it is important to appreciate that this inundation was different from a regular flooding event.