Flood modeling and flood risk analysis of Esmahanim River Catchment, Düzce

Flood is defined as the overflow of water from the channel through which it flows due to heavy rains or the excessive water mass overflowing from its channel and spreading uncontrollably to the surrounding areas. If material damage or disruption in human activities occurs as a result of flood, it is called flood disaster. Not only meteorological reasons but also anthropogenic and topographic factors are effective in the occurrence of flood disasters. Among the topographic factors, slope, aspect, elevation, morphometry of the river bed are some of the important factors that determine the severity and duration of the flood disaster. In addition, due to intense industrialization and urbanization within the framework of human activities, the land is covered with concrete and its infiltration ability is reduced. A large part of the Esmahanım Stream basin, determined as the study area, is located within the borders of Akçakoca district, but also within the borders of Cumayeri and Çilimli districts. As a result of the flood in the study area on 17-18 July 2019, material and moral damages occurred in the villages of Esmahanım, Davutağa, Dilaver and Uğurlu. In this study, flood risk areas in the main branch of Esmahanım Creek were modeled using ArcGIS and HEC-RAS program. The areas that will be inundated as a result of floods have been mapped and risk levels have been determined. According to the findings, in the 500-year scenario corresponding to the highest flow rate, 563 people, 217 buildings, 54.02 hectares of land are at low risk, 353 people, 134 buildings, 45.20 hectares of land are at medium risk, and 106 people, 42 buildings, 53.84 hectares of land are at medium risk. hectares of land are at high risk. Additionally, the flood sensitivity of the basin was analyzed with hydromorphometric analyses. According to the findings, the Gübi sub-basin is the sub-basin with the highest flood sensitivity, while the Esmahanım sub-basin is the basin with medium flood sensitivity and the Küpler sub-basin is the basin with low flood sensitivity.