九份二山地區震災後暴雨流量特性

Stormflow Characteristics in the Chiufenershan Area after the September 1999 Chichi Earthquake

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

《台灣林業科學》 21卷4期 (2006/12) Pp. 499-512

https://doi.org/10.7075/TJFS.200612.0499

摘要

本研究於九份二山崩塌上游與下游地區的韭菜湖溪上游及本流集水區，從事暴雨流量監測，以探討地震造成大崩塌地與堰塞湖的聯合作用對暴雨流量影響。依據5年的暴雨流量監測資料分析，韭菜湖溪本流集水區總暴雨流量率為韭菜湖溪上游集水區的倍數，分年依次為：1.5、1.36、1.14、1.17及1.13。韭菜湖溪本流集水區的總暴雨流量率大於上游集水區，顯示崩塌地對暴雨流量的增加，大於堰塞湖的調節作用；暴雨流量率的增加，逐年漸次減少的趨勢，顯示崩塌地逐漸植生復育工作，已發揮緩和暴雨流量增加的功效。暴雨流量隨暴雨量增加而上升，可用迴歸式，以暴雨量推估暴雨流量，但非線性迴歸式稍優於線性迴歸式。洪峰流量可用線性或非線性複迴歸式，以洪峰到達時間之暴雨量與洪峰到達時間之平均降雨強度，推估洪峰流量。韭菜湖溪上游與本流集水區逕流曲線指數，分別為57與70。韭菜湖溪上游集水區合理化公式之洪峰逕流係數在0.011~0.565間，韭菜湖溪本流集水區洪峰逕流係數在0.008~0.644。

關鍵字

暴雨流量特性 ； 地震 ； 九份二山地區

並列摘要

In this study we monitored stormflow characteristics of the upstream and mainstem watersheds at Chiutsaihu to detect stormflow effects of both the landslide area and landslide-dammed lakes in the Chiufenershan area 5-yr after the Chichi earthquake which was 7.3 on the Richter scale and occurred on 21 September 1999. The Chiutsaihu upstream watershed contains almost no landslide areas. On the contrary the Chiutsaihu mainstem watershed includes a great landslide area and 2 landslide-dammed lakes. Based on analysis of 5-yr stormflow data after the Chichi earthquake, stormflow rates of the mainstem watershed were differentiated from those of the upstream watershed, in order by year as follows: 1.5, 1.36, 1.14, 1.17, and 1.13. Stormflow rates of the mainstem watershed were larger than those of the upstream watershed which showed that the landslide effects were greater than the landslide-dammed lake effects. Gradual vegetation recovery on the landslide areas of the mainstem watershed showed the effects of decreases in the stormflow increases. The stormflow volume increased as storm rainfall increased and could be estimated from a simple regression equation of stormflow volume on storm rainfall. The peak flow was estimated from a multiple regression equation of peak flow on both storm rainfall and average intensity, which were calculated from the beginning of stormflow to the time of the peak. However, nonlinear regression equations were rather better than linear regression equations for estimating the stormflow volume. The curve numbers of the Chiutsaihu upstream and mainstem watersheds determined using the SCS runoff curve number method were 57 and 70, respectively. The ranges of peak flow coefficients in the rational formulae for the Chiutsaihu upstream and mainstem watersheds were 0.011~0.565 and 0.008~0.644, respectively.

並列關鍵字

stormflow characteristics ； earthquake ； Chiufenershan area