Application of Analytical Hierarchy Process and Frequency Ratio Model for Predictive Flood Susceptibility Mapping Using GIS for the Khazir River Basin, Northern Iraq

Abstract

Flood damage assessment is considered the essential tool for evaluating risk to civil and agricultural systems in land use planning. The validity of the studies’ outcome depends on the availability of data and their spatial distribution. The present study came to compute flood susceptibility maps utilizing two application models: (i) the frequency ratio, and (ii) the analytical hierarchy process. These models were then tested in the Khazir River basin using GIS with a selection of twelve flood conditioning factors. The flood inventory variables layer and flood-causing factors were created using remote sensing data, a digital elevation model, and secondary data from various sources. Then, the flood inventory map was highlight divided into training and test data, with 105 flood sites (70%) used for training and 45 sites (30%) used for testing. After applying the areas under the curve for the frequency ratio and analytical hierarchy process models, which were 90.6% and 88.9%, respectively, the final flood sensitivity maps showed similar results for the two models, which confirm the effectiveness of the adopted methodology. The study found a considerable spatial variance in flood sensitivity maps, as (21.06%) of the flooded areas are classified as having very low sensitivity to flooding, (24.09%) are classified as having low vulnerability to floods, and (23.79%) are classified as having moderate vulnerability, (24.10%) classified as highly vulnerable to flooding, and (6.96%) classified as highly vulnerable to flooding. Flood danger ranged from very low in mountain locations to very high in plain areas close to the riverbanks. Obtained results could be improved if a land-use planning policy will be applied, in order to establish a master plan for water resources development to avoid flood damage.