Estimation of flood inundation maps and damage probability curves for non-existing creek flow discharge

Flooding is one type of natural disaster that often has the greatest effect on humans owing to the material and spiritual losses it causes. Because of the rapid change in the world's and the increase in population, often uncontrolled settlement in floodplain. This leads to a significant increase in economic losses due to flooding. In Turkey, the DSİ (State Hydraulic Works) is responsible for taking certain structural measures designed to reduce and minimise the losses and damage caused by these flooding events. One of the regions most affected by flooding is the Akyazı-Küçücek Industrial Zone, which is one of the important industrial areas in Sakarya Province, and for this reason, it was chosen as our study area. This study consists of 5 steps. (1) Repeated flood discharge was calculated using different rainfall flow models. (2) Risk analysis was performed on creek bed structures in the Akyazı-Küçücek Industry Zone. (3) Economic losses because of structural damage likely to occur based on our estimated inundation map were calculated using a flood depth-damage factor. (4) The proposed improvement project was evaluated by DSİ to determine how much it would minimise the economic losses caused by a flooding event. (5) Carrying capacity is calculated for post-breeding. To create flood risk maps in this study, 39 cross sections were taken for the portions of the study area in the industrial zone between 0–150 km and 1–600 km in Küçücek Creek. River, banklines, flow paths and cross sections are digitized in ArcGIS. The obtained data was transferred to the Hec-RAS program. Manning roughness values were assigned to each section, and the sections were rehabilitated. Using hydrological data, recurring flood events of 2, 5, 10, 25, 50, 100, 200 and 500 years were calculated. Flood risk analysis and economic damage estimation were conducted for these events, and our subsequent evaluation of the improvement project provided a comprehensive flood evaluation for the region.