EVALUATION OF THE PROPAGATION TIME OF A THEORETHICAL FLOOD WAVE IN THE CASE OF THE BREAKING OF CATAMARASTI DAM, BOTOSANI (ROMANIA)

Storage lakes represent an important source of water for the areas with a high deficit of hydrologic balance (ex: Moldavian Plain from NE of Romania). This region holds an important number of lakes that allow the storage of water during periods with rainfall shortage. At the same time, they play an important role in the protection of localities against floods. In addition to the benefits that these lakes have, they can also represent a risk factor for the localities situated in the downstream region, in case of dam collapse. In Romania it is widely known the catastrophic event from 1991 when Belci Dam situated on Tazlau River was breached, causing an entire neighborhood from Onesti City to be flooded. The present study focuses on Catamarasti Lake which has a maximum water volume of 12 million cubic meters, the dam being located 3 km upstream of the first locality and the periphery of Botosani City. The proximity of the inhabited areas makes the dam break scenario to be a probable event, therefore the identification of the propagation time of a possible flood wave is essential towards the creation of a system for the protection of the population. The dam break simulation and the quantification of the propagation time of the entire water volume on Sitna river valley is made using HEC-RAS, based on a LiDAR digital elevation model, using the 2D simulation method. In this case, having a likely floodable surface as well as the time in which the flood can reach the nearby localities, there were identified the risk exposed households located in the floodplain, in the vicinity of the river.