曾文水庫集水區崩塌地和土砂流出變遷特性研究

Evolution of Landslide and Sediment Runoff in the Catchment of the Tsengwen Reservoir

陳俞旭(Yu-Shiu Chen) ； 李威霖(Wei-Lin Lee) ； 林健洋(Chien-Yang Lin) ； 蔡雨倫(Yu-Lun Tsai) ； 林士勛(Shih-Hsun Lin)

《中華水土保持學報》 53卷4期 (2022/12) Pp. 273-284

https://doi.org/10.29417/JCSWC.202212_53(4).0006

摘要

氣候變遷加劇崩塌地和土砂流出特性改變，使得土砂災害管理不易。2009年莫拉克颱風重創曾文水庫集水區，加劇崩塌發生與土砂流出。2009年後，降雨事件則較為平穩。為調查莫拉克事件後崩塌地和土砂流出特性，本研究透過衛星影像變異、空載光達數值地形變異、河道泥砂濃度變化和庫容變化等資料來分析。研究顯示近年崩塌復育，河道沖淤幅度變小，泥砂濃度恢復至莫拉克颱風前，且庫容淤積變化趨近於零，說明土砂流出特性恢復平衡狀態。

關鍵字

曾文水庫 ； 土砂流出 ； 率定曲線 ； 遲滯效應

並列摘要

Climate change has resulted in frequent extreme rainfall events, resulting in unpredictable variations in sediment deposition and runoff in reservoirs and their catchments. In 2009, Typhoon Morakot brought lengthy, high-intensity rainfall to the Tsengwen Reservoir watershed, increasing landslides and bare areas and dumping large quantities of sediment into the reservoir. The rainfall cycle in Taiwan remained stable after the 2009 event; however, the Tsengwen Reservoir and its catchment continued to display variations in sediment deposition and runoff, thus warranting investigation. The present study entailed the performance of sedimentation analyses by using satellite images, light detection and ranging digital elevation models, sediment concentration records, and reports on the annual depositional volume in the reservoir. The results revealed that, as of 2020, the ratio of landslide and bare areas in the watershed had decreased, the variations in riverbed topography were minimal, the sediment concentration had returned to its pre-typhoon levels, and the annual deposition into the reservoir was close to zero. This study demonstrated that the variations in sediment runoff and deposition into the Tsengwen Reservoir had returned to equilibrium.

並列關鍵字

hysteresis ； rating curve ； sediment runoff ； Tsengwen Reservoir

參考文獻

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