Assessing urban vulnerability to flood risk. A case study in Batna City, in northeast Algeria

Based on a binary model that takes into account the physical characteristics of the watershed and the different social and economic characteristics of the Algerian city of Batna, we tried to clarify the vulnerable areas to flood risk. The study relied on Geographic information systems and took into account many factors that could affect the response of the watershed, which are the Height, Slopes, Permeability, proximity to major water courses, Topographic wetness index, Drainage density, Normalized Difference Vegetation Index, Height above nearest drainage, the Population density, Housing type, Public equipment and the Population, The research also considers a common area Among four previous studies that was identified as an area at risk, the results indicate a high urban vulnerability in the city centre near Al Maseel and Al-Hizam protection canals and Wadi Al Gourzi. In contrast, the areas of medium vulnerability extend over large areas of the city. These results are related to the change in land use and illegal and legal expansion on non-buildable areas which are supposed to be subject to servitude rights, and these results are mainly due to the physical properties of the watershed, as it provides suitable conditions for the emergence of runoff water, and the low-lying areas of it favor flooding, which can make it difficult to propose economic structural protection measures within the City, which is considered a drainage area for the watershed, and which will be a real obstacle for the authorities to get rid of the flooding problem in the City.