Preparing International Joint Project: use of Japanese flood hazard map in Bangladesh

Abstract

Both Japan and Bangladesh suffer from floods, and variety of measures have been developed in each country. In addition to the structural measures such as embank-ment, non-structural measures such as flood hazard map and warning system have been developed and used for evacuation effectively in Japan. However, flood hazard map is not a common measure in Bangladesh. In Bangladesh, different measures such as raising/elevating their houses with plinth, placing sand bags on the riverbank and migration are common. The major reason of this difference is
because of the different flood phenomena. For example, the flood phenomena in Japan is more destructive in short term compared to the flood in Bangladesh because of the difference of the topography. In Japan, the river velocity is fast because of the steep river bed, therefore, even one hit is possible to destroy buildings and deprive of people’s lives sometimes. However, flood in Bangladesh is not able to destroy buildings and deprive of people’s lives in short term. Long inundation period such as a few months makes people impossible to secure food by farming and deprive of human lives by starvation. Thus, understanding the different flood phenomena is the base of starting project. However, many researchers and mem-bers in international joint projects start without noticing the different phenomena and perception toward river and flood. In addition, understanding the background of each country is also needed, since the technology for flood disaster risk reduction have been developed under the social condition of each country. Since the flood in Japan is destructive in short term, Japanese are afraid of flood, thus flood disaster risk reduction has been considerable interest for government and local people. Government has been developing measures and legislation, and local people are cooperative to the government. However, Bangladeshi are not afraid of flood itself, the flood-conveyed fertile soil is even welcome by farmers. They pay attention to the duration of flood, since it is related to the available duration of farming and securing food. Thus, government and local people in Bangladesh did not choose the way of controlling the river flow by structural measures like Japan.