The maximum discharge of outburst floods caused by the breaching of man-made and natural dams

Abstract

The sudden release of water impounded in natural and man-made reservoirs has been responsible for some major disasters in mountainous regions of the world. Recent natural damming events and failures of natural dams have illustrated the need to examine the nature and magnitude of outburst floods and the behaviour of debris dams in general. An empirical relationship between maximum discharge (Qmax) and volume of water released during the outburst event (Vmax) is established (Qmax = 0.72Vmax0.53) for man-made dams and the relationship is thought applicable to the breaching of natural debris dams (landslides and moraines). This relationship allows a first-order estimate to be made of Qmax in the vicinity of the breach for a given Vmax during the failure of a man-made dam or a natural debris dam. Key words: outburst floods, man-made dams, natural dams, landslide, dam failure.