Flood risk analysis using hydraulic model based on geographical information systems in Kucuk Aksu Creek

In developing countries such as Turkey, the diversity and density of human activities in the river basins greatly increases floods as a result of industrialization and urbanization. Therefore, the hydrological balance of the whole basin deteriorates and large amounts of life and property losses are experienced. In addition, drinking water is polluted as a result of damages in drinking water networks and the transportation structures such as bridge and roads are damaged. For all these reasons, the floods must be accurately estimated and the necessary measures taken. In this study, flood risk areas were determined using the Hec-RAS hydraulic model and the analytic hierarchy process, which is one of the multi criteria decision analyses in Küçük Aksu Creek in the province of Antalya. Firstly, flood recurrence flows were determined with different probability distributions to use on Hec-RAS model. The Kolmogorov-Smirnov test was used to determine the optimal probability distribution. It was analyzed by using the determined flood recurrence flows as inputs of the hydraulic model. As a result of the analysis, the flood propagation and depth maps were formed for the recurrent flows. In addition, structural flood analysis was performed with the depth-damage factor graph. Then, flood risk analysis was performed with analytic hierarchy process (AHP). For this purpose, it was determined seven criteria affecting the flood including slope, precipitation, flow accumulation, distance to stream, land use, aquifer type and soil values. The weights of these determined criteria were calculated and the flood risk map was created by overlapping the weighted criteria in the ArcGIS. Comparing the results of Hec-RAS and AHP, it was seen that that the flood risk areas obtained by these methods were the similar and the AHP method could be used in the flood risk analysis.