Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34180
標題: 台灣河川溪流上游集水區降雨-逕流關係之研究
A Study on Rainfall-Runoff Relationships of Headwater Watersheds in Taiwan
作者: 陳桂如
關鍵字: simple linear reservoir method
簡單線性水庫
storm flow hydrograph
暴雨流量歷線
出版社: 水土保持學系
摘要: Estimation of streamflow hydrographs to storm rainfall is essential in designing hydraulic structures. Most studies on rainfall-runoff relationships are based on Horton's infiltration-exceeded overland flow model. However, in Taiwan's forested watersheds storm flow hydrographs are dominated by flows through subsurface routes. The hydrologic responses of five headwaters watersheds in Taiwan were investigated in this study with the use of a simple watershed model that utilizes the linear storage technique and considers run-off as only two types: fast and slow. Hourly rainfall is separated as input into fast and slow runoff with the use of a non-linear exponential equation. The results show that the parameters of the method is related to that intensity of precipitation. When this method is applied to two different categories of rainfall intensity, it is capable of producing satisfactory results. The results also show that the method appears to underestimate streamflow hydrographs of watersheds where stormflow generation contributions are mainly from infiltration-exceeded overland (surface) flows.
從事洪水預報與工程設計時常需完整之流量資料,但台灣河川溪流之上游集水區常因森林覆蓋、交通不便,甚少設置流量觀測站,故依集水區內之雨量資料來推算集水區集點之逕流歷線乃為水工設計上不可或缺的工作。本研究乃針對台灣河川溪流上游集水區的逕流以地表下逕流為主要產生機制,依據Loukas(1991)所提出之一簡單線性貯蓄模式,其理論為將集水區假想為一組串並聯線性水庫系統,分別代表緩慢逕流及快速逕流之貯蓄水庫,其中快速逕流線性貯蓄水庫是由兩個水庫串聯而成,具有相同貯蓄係數KF,而KS為緩慢逕流貯蓄水庫之貯蓄係數,將到達地面之降雨分成為緩慢逕流貯蓄水庫(Ps=b)及快速逕流貯蓄水庫(Pf=P-Ps)之入流量,並假設水庫貯蓄量S與流出量Q呈線性關連比例,作為來解析單場暴雨的降雨-逕流歷線。本研究選定台灣中、北部五個集水區共41場降雨事件進行流量歷線之模擬,以探討降雨與逕流間關係。 本研究結果發現此模式之緩慢逕流的降雨輸入參數b值會受到降雨強度的影響,而在降雨強度小於20mm/hr時,此研究模式以平均參數模擬時,會有低估流量歷線現象;若考慮降雨強度,將降雨事件分成降雨強度小於20mm/hr及大於20mm/hr後分別模擬,其不管以最佳參數或平均參數模擬所得流量歷線之尖峰流量、暴雨流出量及洪峰發生時間等三特徵值都與實測值相差不大。前人研究曾指出本模式只適合模擬總降雨量大之暴雨事件,但本研究結果顯示,此模式亦適用於降雨強度及總降雨量較小的事件。而以地表逕流為主的暴雨流出量所佔比例較高之集水區,利用此模式推估時則會有低估暴雨流出量現象。 本研究所採用模式其暴雨流出量的產生機制理論較符合森林集水區實際水文現象,而且模式具簡單且易於應用之特性,應可以用來模擬估算台灣森林集水區之流量歷線及水文反應特性以供洪水預報和工程設計之參考。
URI: http://hdl.handle.net/11455/34180
Appears in Collections:水土保持學系

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