Sediment yield during typhoon events in relation to landslides, rainfall, and catchment areas in Taiwan
Sediment yield during typhoon events in relation to landslides, rainfall, and catchment areas in Taiwan
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DOI：
10.1016/j.geomorph.2017.11.007
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发表时间：
2018-02-15
期刊：
影响因子：
3.9
通讯作者：
Chao, Yi-Chiung
中科院分区：
文献类型：
--
作者：
Chen, Chi-Wen;Oguchi, Takashi;Chao, Yi-Chiung
山体滑坡产生的碎石会造成环境问题，例如河流中泥沙排放量增加。本研究分析了台湾17条主要河流在14次台风期间的泥沙流量，这些台风是根据政府报告的集水区和河流长度选择的。利用台湾水利局各水文站所测得的悬沙量和排水量，建立了它们之间的幂律关系。利用分级曲线法和日排水量实测资料估算了台风期间的输沙量。各河流输沙量与降雨条件正相关，表明台风期间降雨量越大或降雨强度越大，输沙量就越大。此外，台风期间的输沙量主要受降雨总量的控制，而不受峰值降雨量的控制。河流之间相关方程的差异表明，面积越大的集水区产生的泥沙越多。输沙量相对较低的流域随着降雨的增加，输沙量的增加更为明显，这是由于与河流连通性高的小流域的沉积机会很少，以及台风事件期间大部分滑坡碎屑被输送到河流中。此外，台湾周边流域地貌地质条件的差异导致悬沙动力学和泥沙收支的差异。台风期间的平均输沙量与滑坡平均面积呈正相关关系，说明台风期间的强降雨造成较大的滑坡时，更多的最新滑坡碎屑松散物质被冲入河流，导致更大的输沙量。台湾的大滑坡比例很高，这对台湾的年产沙量有很大的贡献，尽管台湾面积很小，但台湾的年产沙量是世界上最高的。(C) 2017 Elsevier B.V.版权所有
Debris sourced from landslides will result in environmental problems such as increased sediment discharge in rivers. This study analyzed the sediment discharge of 17 main rivers in Taiwan during 14 typhoon events, selected from the catchment area and river length, that caused landslides according to government reports. The measured suspended sediment and water discharge, collected from hydrometric stations of the Water Resources Agency of Taiwan, were used to establish rating-curve relationships, a power-law relation between them. Then sediment discharge during typhoon events was estimated using the rating-curve method and the measured data of daily water discharge. Positive correlations between sediment discharge and rainfall conditions for each river indicate that sediment discharge increases when a greater amount of rainfall or a higher intensity of rainfall falls during a typhoon event. In addition, the amount of sediment discharge during a typhoon event is mainly controlled by the total amount of rainfall, not by peak rainfall. Differences in correlation equations among the rivers suggest that catchments with larger areas produce more sediment. Catchments with relatively low sediment discharge show more distinct increases in sediment discharge in response to increases in rainfall, owing to the little opportunity for deposition in small catchments with high connectivity to rivers and the transportation of the majority of landslide debris to rivers during typhoon events. Also, differences in geomorphic and geologic conditions among catchments around Taiwan lead to a variety of suspended sediment dynamics and the sediment budget. Positive correlation between average sediment discharge and average area of landslides during typhoon events indicates that when larger landslides are caused by heavier rainfall during a typhoon event, more loose materials from the most recent landslide debris are flushed into rivers, resulting in higher sediment discharge. The high proportion of large landslides in Taiwan contributes significantly to the high annual sediment yield, which is among the world's highest despite the small area of Taiwan. (C) 2017 Elsevier B.V. All rights reserved.