Flood map production and evaluation of flood risks in situations of insufficient flow data

Flooding, which is the most commonly occurring disaster worldwide, causes the loss of life, injuries and illnesses, psychological trauma and social disruption and damages private and public property and the natural environment. The aim of this study was to complete flood modeling of the Ceviz Stream, which passes through flood-prone Ceviz village, located on a major coastal highway in Ordu Province in the Eastern Black Sea Region of Turkey. More intense rainfall events in the region due to the impact of climate change have led to an increase in flood events in recent years. Due to insufficient flow data in the study area, synthetic unit hydrograph methods were used to estimate flood flow rates. A MIKE FLOOD 1D/2D coupled model was used to describe the overflow zones. The model was calibrated with the data from the major flood event in 2018. Modeling results were assimilated into the ArcGIS environment and different types of flood danger maps were created. Flood risk was calculated with the Dinh, FRMG and FEMA methods, and the results were compared. The results of the study demonstrated that people in Ceviz village and public and private assets are under considerable threat of flooding. Government agencies in Ordu Province can use the generated data and mapping to assist in the development of a holistic suite of policies, plans and actions that minimize the societal and economic impacts of flooding on Ceviz village and coastal highway users.