Compilation of historical floods catalog of northwestern Algeria: first step towards an atlas of extreme floods

Floods are among the significant natural hazards in Algeria. They cause severe casualties, damage to building and destruction of roads, public works, and infrastructures. Northwestern Algeria has experienced devastating floods in the past that caused considerable damage, e.g., Mohammadia 1881, Mostaganem 1927, and El Asnam 1966. Analysis of historical floods is one of the major tools in flood hazard assessment that enables predicting future flood events. One of the objectives of this work is to address the gap of available information regarding the floods that happened in Algeria, particularly during historical times. The first historical data analysis that we performed on the basis of an intensive survey shows that the study area is subject to flooding. This inventory is the first step towards flood zonation and construction of an atlas of extreme floods in northwestern Algeria. The catalog of historical floods contains more than 127 documented events. As results, this paper presents a method of compiling historical flooding data and the analysis of the obtained database which represents a major contribution to flood risk assessment.