An evaluation on the parameters used in flood susceptibility analysis

Abstract

Floods are increasingly important disasters worldwide and Türkiye due to their increasing magnitude and frequency. The main purpose of this study is to evaluate the international and national literature on flood susceptibility and to determine the flood susceptibility parameters based on the watersheds of the settlements where floods occur, as a new approach to susceptibility studies. Accordingly, in study, depending the historical flood inventory, flood susceptibility analysis parameters were determined according to the basins of the settlements where floods are experienced on the valley floor and riverside within the borders of Bursa province. The primary data used in the study are inventory data covering the period between 1956-2022, 5m resolution Digital Elevation Model (DEM) of Bursa province, hydrological soil groups (HSG) and precipitation data (WorldClim). According to the historical flood inventory occurring within the borders of Bursa province, 28 settlements and their watersheds were identified and 12 flood causative parameters were applied to these basins. These flood causative parameters were normalised to between 0-1 in the classification stage and parameter coefficients for flood susceptibility were created according to the result. In this direction, bifurcation ratio, drainage density, time of concentrations, slope, topographic wetness index, stream power index and hydrologic soil groups were determined as the parameters with maximum effect according to the inventory. As a result, in this study, unlike previous studies in flood susceptibility analysis, flood susceptibility parameters were determined from the basins of the settlements where floods occur in the inventory.