台灣南部中寮溪森林集水區暴雨流量特性

Stormflow Characteristics of the Chungliaoshi Forested Watersheds in 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)

《中華水土保持學報》 41卷2期 (2010/06) Pp. 50-75

https://doi.org/10.29417/JCSWC.201006_41(2).0004

摘要

本研究於中寮溪上游與主流森林集水區，從事暴雨流量監測，以探討面積差異甚大的兩個森林集水區，其暴雨流量的特性。依據5年的暴雨流量監測資料分析，中寮溪上游森林集水區總暴雨流量率，分年依次爲：34.18%、37.08%、54.02%、49.06%及33.01%；中寮主流森林集水區總暴雨流量率，分年依次爲：21.80%、28.70%、41.02%、46.32%及28.80%；中寮溪上游森林集水區總暴雨流量率爲中寮溪主流森林集水區的倍數，分年依次爲：1.57、1.29、1.32、1.06及1.15。中寮溪上游森林集水區的總暴雨流量率大於中寮主流森林集水區，顯示植生覆蓋相似時，面積較小的中寮溪上游森林集水區暴雨流量率，比面積較大的中寮溪主流森林集水區暴雨流量率爲大，也就是面積愈大的森林集水區，愈能發揮緩和暴雨流量率的凾能。暴雨流量隨暴雨量增函而上升，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。中寮溪上游與主流森林集水區逕流曲線指數，分別爲57與48。中寮溪上游森林集水區合理化公式之洪峰逕流係數在0.006~0.449間，中寮溪主流集水區洪峰逕流森林係數在0.004~0.601。

關鍵字

暴雨流量特性 ； 洪峰流量 ； 森林集水區

並列摘要

Stormflow characteristics of the Chungliaoshi upstream and mainstem forested watersheds were monitored to detect effects of large and small forest cover area on stormflow from 2004 to 2008. Based on analysis of 5-yr stormflow data in order by year as follows, stormflow rates of the upstream forested watershed were 34.18%, 37.08%, 54.02%, 49.06%, and 33.01%; stormflow rates of the mainstem forested watershed were 21.80%, 28.70%, 41.02%, 46.32%, and 28.80%; as well as stormflow rates of the upstream forested watershed were differentiated from those of the mainstem forested watershed as follows 1.57, 1.29, 1.32, 1.06, and 1.15. Stormflow rates of the upstream forested watershed were larger than those of the mainstem forested watershed which showed that the effects of large forest cover area to reduce stormflow rates were greater than the effects of small forest cover area. 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 Chungliaoshi upstream and mainstem forested watersheds being determined using the SCS runoff curve number methods were 57 and 48, respectively. The ranges of peak flow coefficients in the rational formulae for the Chungliaoshi upstream and mainstem forested watersheds were 0.006~0.449 and 0.004~0.601, respectively.

並列關鍵字

stormflow characteristics ； peak flow ； forested watershed