ACTA GEOBALCANICA 5-1, 2019, pp. 35-41 35 EVALUATION OF THE PROPAGATION TIME OF A THEORETICAL FLOOD WAVE IN THE CASE OF THE BREAKING OF CATAMARASTI DAM, BOTOSANI (ROMANIA) DOI: UDC: https://doi.org/10.18509/AGB.2019.05 627.82-044.377:627.51(498) Liviu-Marian Albu 1 , Andrei Enea 1, 2 , Cristian-Constantin Stoleriu 1 , Iosub Marina 1, 2 , Gheorghe Romanescu 1 , Hutanu Elena 1 1 Alexandru Ioan Cuza University of Iasi, Faculty of Geography and Geology, Department of Geography, Romania 2 Integrated Center of Environmental Science Studies in the North Eastern Region-CERNESIM, Alexandru Ioan Cuza University of Iasi, Romania corresponding author: albuliviumarian@gmail.com submitted: accepted: published: 25.02.2018 05.06.2018 01.11.2018 Abstract 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 Tazlău 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. Keywords: dam, HEC-RAS, lake, management, simulation INTRODUCTION The absence of water in certain regions, the very high probability of flooding or the necessity for generating electric power are some of the main reasons which stood at the basis of the human desire to store water in lakes. Anthropic lakes have the capability to bring a multitude of benefits to the nearby population and settlements, but at the same time the existence of these water bodies can represent a great risk for the populations and settlements located downstream [1]. This risk exists through the possibility of the dam (behind which the stream water accumulates), to be breached or to break [2]. One of the most recent events of this type, which implied a dam being exposed to breaking, was the event from February, 2017, at Oroville Lake from California, USA, when a number of approximately 188 000 persons were evacuated. This particular event was one fortunate scenario, because no casualties were recorded [3]. In contrast, perhaps the biggest disaster of this kind was the one that took place in China, when the Banqiao and Shimantan dams breached in 1975, causing the loss of over 171,000 human lives, 26,000 from flooding and the other 145,000 from famine and water-related disease [4]. Until present, a number of over 2000 dam breaks that had different impacts on society have been recorded, and most of the events of this kind were registered between 1900 and 2000, when the construction of dams has seen an acceleration, due to the ever- increasing need of such hydrostructures [1], [2]. In Romania, a single hydrotechnical accident of high amplitude was registered, in July 1991, when the Belci Dam, constructed on Tazlau river, breached