Flood hazard mapping using FLO-2D and local management strategies of Dire Dawa city, Ethiopia

This study was conducted in Dire Dawa city of Ethiopia, where flood hazard occurs on regular basis. The study was conducted with the aim of mapping flood hazard and exploring local flood risk management strategies. As to flood mapping, FLO-2D hydrodynamic model was employed to identify flood prone villages. FLO-2D was chosen for its versatility to use different data sources. To identify local flood management strategies, household survey was conducted on 232 households located in flood prone areas. The final result of flood hazard map identified about 1163 buildings located inside high, medium and low flood hazard zones. The validity of the FLO-2D model versus ground truth was statistically tasted and showed a strong positive correlation. Flood smell, cloud direction, extreme weather and gunshot were identified as the locally used flood early warning strategies. Even if, the local flood risk management strategies have helped to reduce the level of vulnerability at normal condition, the gap is observed when extreme events are recorded. It is highly recommended that the flood hazard map developed for the city and existing flood management strategies are properly utilized for future flood risk planning of Dire Dawa city and its watershed.