Comprehensive Study on Floods and Storm Surges in Bangladesh and Their Hazard Mitigation

由于雅鲁藏布江、恒河和梅赫纳河这三条大河的泛滥以及低洼地区的积水，孟加拉国一再遭受广泛破坏。此外，在孟加拉湾发展的气旋经常袭击沿海地区，造成严重的灾害。研究的目的是通过实地调查，收集和处理与洪水和风暴潮有关的数据，弄清洪水和气旋灾害的实际情况，为减轻这些灾害提供信息和技术数据。(1)研究了过去造成严重破坏的降水型和天气条件的时空特征，以找出暴雨的原因。(2)基于遥感数据，分析了地形与洪水条件的关系。(3)降雨径流分析及有限元…二维洪水数值模拟。对低洼地区降雨径流特征和淹没过程进行了较为深入的模型研究。(4)对梅格纳大桥附近河岸侵蚀和泥沙输移进行了现场研究。(5)基于沿海低地地形资料、潮汐观测资料和气象资料，对孟加拉东南部地区的风暴潮进行了数值模拟。(6)对孟加拉东南部沿海地区1991年发生的气旋风暴潮进行了现场观测。(7)对洪水灾害预报、预警和疏散系统进行了评价。此外，还对孟加拉洪涝风暴潮灾害非建筑物防御措施存在的问题和任务进行了分析，这些实地调查和分析的结果将有助于改进和制定孟加拉国洪灾和气旋灾害的应对措施。较少

Bangladesh has suffered repeatedly extensive damage by flooding of the three huge rivers, the Brahmaputra, the Ganges and the Meghna and by the stagnation of water in low-lying area. Furthermore, cyclone which develops in Bengal Bay often attacks coastal areas, causing severe disaster.The objectives of the study are to clarify the actual circumstances of the flood and cyclonic disasters through the field investigation, gathering and processing data related to floods and storm surges and to provide information and technical data to mitigate these disasters.(1) The spatial and time characteristics of the precipitation patterns as well as the synoptic conditions which brought heavy damages in the past have been examined in order to find out the cause of the heavy rainfalls.(2) Based on the remote-sensing data, relationships between the landform and flood conditions have been analyzed.(3) The rainfall runoff analyzes and the numerical simulation of 2 dimensional flood flow with finite elem … More ent model have been carried out to clarify the characteristic of rainfall runoff and process of inundation in low-lying area.(4) Field researches on river bank erosion and sediment transport have been conducted near the Meghna Bridge. Hydraulic and Geotechnical discussion on their results clarified the mechanisms of bank erosion and river bed variation.(5) Based on the topography data in coastal lowland, observed tidal records and meteorological data, the numerical simulation of storm surge have been carried out in the southeast region of Bangladesh.(6) The field survery of the wind-induced failure by the cyclone of 1991 have been carried out in the southeast coastal region.(7) Forecasting, warning and evacuation systems against flood disaster have been evaluated. Moreover, problems and tasks of non-structure prevention measures against flood and storm surge disasters have been examined.These results of field investigations and analyzes will contribute to the improvement and establishment of the countermeasures against flood and cyclonic disasters in Bangladesh. Less