Flood simulation on the Vedea River in Alexandria, Romania, using hydraulic modelling and GIS techniques

Abstract

Flooding occurs yearly in region across Europe, including Romania, when water accumulates at heavy rainfalls, favored by natural and anthropogenic factors such as a flat slope of the meadow, elongated shape of the valley or buildings located close to the river. Alexandria is a city affected by flooding. The study wants to analyze the flood that took place from 3rd to the 6th of July 2005 and the hypothetical impact that could have occurred on the city in the situation of a dam break. The analysis was done based on field observations, hydraulic modeling in HEC-RAS 6.2, GIS techniques (ArcMap) and flow data from the Romanian National Institute of Hydrology. At the beginning, data was imported in ArcMap in order to be prepared with the help HEC-GeoRAS extension for hydraulic modeling in HEC-RAS. After running the simulation, the flooded area was obtained and imported back into GIS. Thus, the number flooded buildings and affected roads have been determined using different tools in ArcMap. There is a high potential for flooding in Alexandria in case the dam would break, especially with high rainfall such as in 2005 when the flow value of 676 m3/s was reached, 80 times higher than the normal flow.