Dam-break Floods Downstream Of Papadia Dam

Abstract

The propagation of a flood resulting from a dam failure has been investigated by several engineers over the last decades. Many algorithms have been developed for the solution of the Saint-Venant equations, governing the flow propagating downstairs in natural channels, after a dam failure. The algorithms are based on characteristic equations, finite difference equations, and finite element equations and describe the flood propagation through the channels. As the breach formation's mechanics are not well understood in previous attempts to predict flood waves downstream, it was assumed that the dam failure was complete and instantaneous Only over the last years has the breach formation of a dam been the subject of engineers' research and the breach was assumed to develop over a finite interval of time. In this paper the dam breach formation of Papadias dam (North Greece) has been investigated, and the propagation of the flood through the stream and the valley downstream is described. A rather empirical model due to Fread predicting the time of the dam failure and the geometric breach evolution of the dam is considered. For routing dam-break flood waves a particular hydraulic algorithm is chosen. The geometric and physical characteristics of the stream and valley downstream for a distance of 30 km have been chosen from maps and by measurement in situ. Different scenarios concerning the Papadia dam failure have been considered and for each of them flood hydrographs of water depth and discharge have been calculated.