六龜試驗林中寮溪溪床變化與溪流穩定評估

Streambed Variation and Channel Stability Evaluation of the Chungliao Creek at Liukuei Experimental Forest of Southern Taiwan

盧惠生(Hui-Sheng Lu) ； 林壯沛(Jaung-Pey Lin) ； 黃良鑫(Liang-Shin Hwang) ； 林介龍(Chieh-Lung Lin) ； 王秋嫻(Chiu-Hsien Wang)

《坡地防災學報》 8卷1期 (2009/05) Pp. 15-24

https://doi.org/10.29995/JSHR.200905.0002

摘要

台灣每年遭受颱風侵襲所挾帶之豪雨量，差異頗大，最大河溪水流搬運石礫與沖刷溪床能量變化多端，是故不易明瞭上游森林集水區溪床與溪流穩定變化特性。本文乃以水準儀測量中寮溪3個溪段的溪床橫斷面變化，同時以美國農部林務署發展之溪流穩定評估法，探討中寮溪的溪床變化特性與溪流穩定狀態。中寮溪上游段、中游段、下游段三段溪床，於2005~2007年3年間溪床沖淤變化，在-19.0~94.3cm間，3年間溪流穩定狀態評估值變化，在81~123間，等級在較佳至尚可間，主要影響因子為溪床兩岸崩塌地與颱風侵襲挾帶之豪雨。沖淤深度絕對值與溪流穩定評估值成正相關，顯示溪流穩定評估值愈大時，溪流穩定度愈差，沖淤深度絕對值愈大。溪流穩定評估因子中的沖蝕或崩塌、堆積物、淘刷作用、堆積作用、淘沙與（或）淤積、障礙物與彎曲河道及囚砂、泥砂粒徑分布及安定顆粒比率等7個評估因子，與沖淤深度絕對值頗有關聯。

關鍵字

溪床變化 ； 溪流穩定 ； 中寮溪

並列摘要

The rainfall amount and intensity of typhoon were rather different every year. The moving gravel size and souring energy of streambed by annual maximum stream flow were also varied. Therefore, the characteristics of streambed variation and channel stability were not easy understood. Measuring characteristics of cross section variations with levelling and evaluating conditions of channel stability with procedure original from Forest Service of United States for streambeds of three reaches along Chungliao creek were carried out in this study. The scouring-deposition depths on streambeds of three reaches along Chungliao creek were between -19.0 cm and 94.3 cm from 2005 to 2007 year. The scores of channel stability indicators were between 81 and 123 and their ranks were from fair to good during three years from 2005 to 2007 year. The variations of scouring-deposition and channel stability indicators on these three reaches for three years were affected by landslide areas along streamside as well as rainfall amount and intensity being carried by typhoon. The absolute values of scouring-deposition depths were positively responding with the variation of channel stability indicators. The absolute values of scouring-deposition depths increased as channel stability indicators increased and channel stability conditions become worse. The major seven factors in channel stability indicators affecting the absolute values of scouring-deposition depths were as follows: mass wasting, debris jams potential, cutting, deposition, scouring, obstruction, and particle packing.

並列關鍵字

Streambed variation ； Channel stability evaluation ； Chungliao creek