集水區土砂脈衝現象之研究

A Study on Pulsing Sediment for Watersheds

10.29417/JCSWC.201103_42(1).0002

蔡真珍(Chen-Chen Tsai)；林昭遠(Chao-Yuan Lin)

系統生態學 ； 土砂脈衝 ； 生態模型 ； 集水區治理 ； system ecology ； pulsing sediment ； eco-model ； watershed mitigation

中華水土保持學報

42卷1期（2011 / 03 / 01）

12 - 22

繁體中文

集水區土砂災害可視為一脈衝現象，當土砂能量集中輸出時，系統所產生之振盪作用，通常危害人類社會甚鉅，歷史之土砂災害事件在在顯示土砂防治工作之重要性與困難度。本研究回顧國外脈衝相關文獻並以台灣案例為分析樣區，瞭解自然界存在之脈衝現象及脈衝能量之破壞力與平衡作用，另配合系統生態學理論及其生態能量分析方法建置脈衝生態模型，探討自然災害在系統組成及能量流動中之交互作用，並模擬颱風豪雨時之崩塌事件，所產生之土砂脈衝型態。由翡翠水庫集水區案例分析可知，土砂脈衝現象除了與自然外部脈衝能量（雨量）有關外，亦與系統內部可供應能量（土砂量）有關；另透過系統模擬，分析結果顯示低頻率之脈衝能量高，系統產生較大之振盪，相對易造成災害事件。在集水區土砂治理計畫中建議考量可分次釋放土砂能量之整治措施，避免能量累積效應，並可使集水區生態系統維持較佳之自我組織之能力。

The centralized output of sediment energy in watersheds can be regarded as the oscillation of pulsing energy to the system and it has catastrophic impact on humans. This paper presents the pulsing phenomenon existing in the nature to interpret destructive power as well as the balance of pulsing energy. Meanwhile, this study discussed the interaction of the system constitution and energy flow in natural hazards by establishing a pulsing eco-model based on the system ecology approach. The magnitude of pulsing sediment has a close relationship between the concentrated rainfall and the available materials of sediment from the case study of Feitsui reservoir watershed. The results of simulation showed that a higher magnitude pulsing occurs less frequently but causes hazards more easily. To prevent hazardous pulsing sediment, the effect of energy accumulation should be considered in sediment mitigation, and thereby enables the watershed ecosystem with a better function of self-organization.