2015 年 71 巻 5 号 p. I_23-I_28
River floods are natural disasters that affect millions of people every year. In addition, vast areas of floodplains used for cattle farming are inundated annually, and animals often drown. Depending on the floodplain characteristics, the floods can last for several days or even months. Even if the water depth is not sufficient to drown cattle, the long exposure to flood water may cause diseases. Thus, it is important to define safe zones and to identify safe routes for cattle to reach such zones.
This study proposes flood evacuation zones for cattle in the Llanuras de Mojos (in the Bolivian Amazonia), based on the results of a two-dimensional flood simulation using a flood inundation model. Flood simulations provided the daily variation in the extent and depth of flooding. These results enabled flood hazard zones to be defined for cattle on different days. It was found that the left margin of the Mamore River was the most hazardous zone, with flood depths that were likely to drown cattle. The best evacuation route was identified as the right bank of the Mamore River located on the northern edge of the city of Trinidad.