A GIS-based integration of catastrophe theory and analytical hierarchy process for mapping flood susceptibility: a case study of Teeb area, Southern Iraq

A novel method has been proposed in this study for delineation of flood-prone areas through integration of catastrophe theory and analytical hierarchy process (AHP) in a geographical information system. Seven causative flood factors were selected for this purpose based on data availability and literature reviews, namely, ground surface elevation, slope angle, curvature, topographic wetness index, stream power index, curve numbers, and distance from intermittent streams. The raster maps of the factors were prepared with a cell size of 30 x 30 m. The catastrophe models were used to derive weights of the factors using weighted linear combination technique, while AHP was used to compute normalized ranks of the classes of each factor. The model was applied to demarcate the flood-prone zones in northeastern parts of Southern Iraq, where flash flood is a recurrent natural hazard that causes damage to property almost every year. The study revealed that about 852 km(2) (41 %) of the study area is less susceptible, 434 km(2) (21 %) is moderate susceptible and 812 km(2) (38 %) is high susceptible to flood. The high flood-susceptible zones are mainly distributed around the intermittent streams and the low lands in the southeast, while the low flood-susceptible zones are found in the east and northeast hilly regions of the study area. The obtained result matches well with general conception of flood-prone zones in the region, which indicates that integration of catastrophe theory and AHP can provide a low cost and easily implementable method for reliable mapping of flush flood-susceptible zones.