Influence of dam break scenarios on flood wave characteristics. Case study – Paltinu Dam, Romania

Abstract

Among the various constructive types of dams, the arch dams breaches are the largest and the quickest to occur, leading to the most catastrophic flood waves. Therefore, prediction of the shape, magnitude and arrival time of the breach waves is of utmost importance for flood risk management. The study analyses in GIS environment the influence of different dam breach scenarios on the evolution in time and space of the flood wave. As a study case it was chosen the 108m in height, Paltinu arch-dam (Romania), built on Doftana River and its about 19km river reach down to the confluence with Prahova River. Several breach widths and depths are considered in the analysed scenarios, coupled with selected inflow hydrographs and initial reservoir water elevation, to assess their influence on the dam break wave characteristics and downstream flooded areas. To model the flood wave routing following the dam brake, HEC-RAS software is used. Inundation boundaries, characteristic depths and velocities, as well as arrival time in selected control sections are compared and conclusions are drawn.