During 29–31 September 2019, tropical storm Podul moved into the Kaeng Lawa sub-watershed (KLs), the upstream area of the Chi watershed, causing the worst flooding in 40 years. This study was carried out to analyze the watershed characteristic (WC) variables and prioritize the risks of land-use patterns in KLs, Khon Kaen Province, using a watershed delineation approach. As a result of this study, of the 11 sub-watersheds in the Kaeng Lawa watershed, only KL03 and KL04 were deemed medium priority within their drainage and storage capacity systems. KL01, in the upstream sub-watershed, displayed very low priority. The pattern of land-use that appeared most in KL01 sub-watershed was deforestation, where the upper forest area appeared to show a 63% decrease from 2002 to 2017. The decreased forest area was replaced with agricultural area, for crops such as sugarcane and para-rubber, and fruit farms. Moreover, increases in urban area expansion were found in the downstream area in the north of KLs. The findings of this study reveal that severe flooding in this area was caused not only by tropical storm Podul, but also by the low prioritization of watershed characteristics and patterns of land-use that resulted in decreasing forested area in this watershed area. Consequently, these factors have influenced watershed storage and caused an accumulation of water volume, which regularly results in floods. Thus, flood mitigation should be implemented urgently, in the very low priority areas of the study area first.

中文翻译：

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使用形态测量和土地利用分析对孔敬省 Kaeng Lawa 子流域进行流域优先排序：热带风暴 Podul 造成的严重洪水的案例研究

2019 年 9 月 29 日至 31 日，热带风暴 Podul 进入 Chi 流域上游地区 Kaeng Lawa 子流域 (KLs)，造成 40 年来最严重的洪水。进行这项研究是为了分析流域特征 (WC) 变量，并使用流域划分方法对孔敬省 KL 的土地利用模式的风险进行优先排序。根据这项研究，在 Kaeng Lawa 流域的 11 个子流域中，只有 KL03 和 KL04 被认为是其排水和存储能力系统中的中等优先级。KL01 位于上游子流域，显示出非常低的优先级。KL01子流域出现最多的土地利用格局是森林砍伐，2002年至2017年，上层森林面积似乎减少了63%。减少的森林面积被农业面积取代，用于甘蔗和副橡胶等作物以及水果农场。此外，吉隆坡北部下游地区的市区扩张有所增加。这项研究的结果表明，该地区的严重洪水不仅是由热带风暴 Podul 造成的，而且是由于流域特征和土地利用模式的低优先级导致该流域地区的森林面积减少。因此，这些因素影响了流域蓄水并导致水量积累，从而经常导致洪水。因此，应紧急实施防洪措施，首先在研究区的低优先级区域。这项研究的结果表明，该地区的严重洪水不仅是由热带风暴 Podul 造成的，而且是由于流域特征和土地利用模式的低优先级导致该流域地区的森林面积减少。因此，这些因素影响了流域蓄水并导致水量累积，经常导致洪水。因此，应紧急实施防洪措施，首先在研究区的低优先级区域。这项研究的结果表明，该地区的严重洪水不仅是由热带风暴 Podul 造成的，而且是由于流域特征和土地利用模式的低优先级导致该流域地区的森林面积减少。因此，这些因素影响了流域蓄水并导致水量积累，从而经常导致洪水。因此，应紧急实施防洪措施，首先在研究区的低优先级区域。这经常导致洪水。因此，应紧急实施防洪措施，首先在研究区的低优先级区域。这经常导致洪水。因此，应紧急实施防洪措施，首先在研究区的低优先级区域。