Optimal model for selecting evacuation routes in flood-prone areas based on 2D hydrodynamic processes and its application

The evacuation distance and water depth are regarded as the key factors in flood events, and the flooding process and the temporal-spatial distributions of victims would influence greatly on the choice of opportunity and route of evacuation. The model for selecting optimal escape route in flood-prone areas is proposed based on the two-dimensional hydrodynamic model. It would direct the flood victims away from danger, but also provide a rational basis for construction of road networks. The Dijkstra algorithm is adopted to derive the shortest routes, the effect of the flood conditions on the escape speed is considered, and the optimal refuge and escape route is selected based on the stability of the human body and the final escape moment. Finally, the optimal escape routes were selected for two overbank flood events in July 1958 and August 1982 in the Lankao-Dongming floodplain area in the Lower Yellow River. The variations of risks for people in floodwaters were analyzed, and the locations and corresponding final escape moments of optimal escape routes were determined for three disaster locations in these two flood events. The results indicate that there would be 3-6 hours more for evacuees if they escape on the optimal routes. The locations of optimal escape routes for these two flood events were the same, but the final escape moments would be earlier in the 1958 flood event because of the larger amount of water volume and higher peak discharge. © 2017, China Water Power Press. All right reserved.