The use of watershed geomorphic data in flash flood susceptibility zoning: a case study of the Karnaphuli and Sangu river basins of Bangladesh
The use of watershed geomorphic data in flash flood susceptibility zoning: a case study of the Karnaphuli and Sangu river basins of Bangladesh
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DOI：
10.1007/s11069-019-03749-3
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发表时间：
2019-10-01
期刊：
影响因子：
3.7
通讯作者：
Abdullah, Abu Yousuf Md
中科院分区：
文献类型：
--
作者：
Adnan, Mohammed Sarfaraz Gani;Dewan, Ashraf;Abdullah, Abu Yousuf Md
孟加拉国东南部丘陵地区的暴雨使该地区极易发生经常性山洪暴发。由于该地区是孟加拉国的商业首都，这些山洪暴发对国民经济构成重大威胁。预测这种类型的洪水是一项复杂的任务，需要详细了解流域特征。这项研究评估了该地区对Karnaphuli和Sangu河流域山洪暴发的敏感性。使用了22个形态学参数。流域内山洪的发生和影响主要与流域径流量、径流流速和地表入渗能力有关。分析表明，该盆地的主要部分容易受到“中度”至“非常高”严重程度的山洪暴发事件的影响。其中10个流域的敏感程度被评为“高”，1个为“非常高”。从分析中得出的暴洪敏感性图被用于分区一级，以确定面临风险的人口稠密地区。16个分区总面积的80%以上被确定为具有“高”至“非常高”级别的洪水敏感性。分析指出，约有340万人居住在山洪暴发易发地区，因此表明有可能造成生命和财产损失。该研究确定了一个国家重要地区内的重大山洪暴发潜在区域，以及人口对这些事件的暴露程度。详细分析和显示分区一级的山洪灾害敏感性数据，可以使相关组织改善流域管理做法，从而减轻未来的洪水风险。
The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial capital of Bangladesh, these flash floods pose a significant threat to the national economy. Predicting this type of flooding is a complex task which requires a detailed understanding of the river basin characteristics. This study evaluated the susceptibility of the region to flash floods emanating from within the Karnaphuli and Sangu river basins. Twenty-two morphometric parameters were used. The occurrence and impact of flash floods within these basins are mainly associated with the volume of runoff, runoff velocity, and the surface infiltration capacity of the various watersheds. Analysis showed that major parts of the basin were susceptible to flash flooding events of a 'moderate'-to-'very high' level of severity. The degree of susceptibility of ten of the watersheds was rated as 'high', and one was 'very high'. The flash flood susceptibility map drawn from the analysis was used at the sub-district level to identify populated areas at risk. More than 80% of the total area of the 16 sub-districts were determined to have a 'high'-to-'very-high'-level flood susceptibility. The analysis noted that around 3.4 million people reside in flash flood-prone areas, therefore indicating the potential for loss of life and property. The study identified significant flash flood potential zones within a region of national importance, and exposure of the population to these events. Detailed analysis and display of flash flood susceptibility data at the sub-district level can enable the relevant organizations to improve watershed management practices and, as a consequence, alleviate future flood risk.