- 作者: 王如意
- 作者服務機構: 國立臺灣大學農工系
- 中文摘要: 臺灣之集水區,山高河短、坡陡流急,地質情況特殊。由分析洪水歷線可歸納得知本省之水文特性具閃速洪峰流量、短暫洪峰時間與微小退水係數。因之,供水歷線甚可能由一短促延時、強烈暴雨所造成者。此類短小延時之單位歷線可以那徐氏線性水庫之概念模式比類集水區之瞬時單位歷線。每一集水甚之瞬時單位歷線可輔以電子計算機解出且點繪之。兩瞬時單位歷線參數-Gamma函數因子N與水庫儲存常數K,與集水區之面積、主要河流長度、重心距及河糟平均坡度相關。 線性模式之重疊原界可應用於臺灣集水區洪水歷線分析。是故,考慮不同上程向的之洪水再發生年數之洪峰設計可參老規劃地區之暴雨深度—面積—類率圖表與其土地利用、土壤條件直接乘以設計逕流求之。 以瞬時單位歷線法分析洪水歷線乃近年來水文研究之一新顆方法,蓋有效雨量之短暫延時與實際由瞬時驟雨所形成者相近矣。本研究並以數學參數方式以簡化水文歷線之分析。
- 英文摘要: Watersheds in Taiwan can be characterized by their particularly hydrologic andgeologic conditions. A typical Taiwanese watershed has a flash peak, short time topeak, small recession coefficient, comparatively small area, steep river and ruggedtopography. The typical characteristics of a flood hydrograph of a watershed in Taiwan canbe shown through the evaluation of two time parameters of the hydrograph, time topeak, t ,and recession coefficient, K , which are both small. The flood hydrographare most likely produced by an intense storm of short duration. Such a short dur-ation hydrograph can be used to develop an instantaneous unit hydrograph by usingNash's conceptual model. The instantaneous unit hydrograph for each watershedcan then be solved by an electronic computer. The two instantaneous unit hydro-graph parameters, Gamma function argument, N, and reservoir storage constant, K,were found to correlate with watershed area, length of main stream, centroid distanceof the basin and average slope of the channel. The superposition principle of a linear model can be applied for hydrographanalysis of important watersheds in Taiwan. Hence, the design discharge with ce-rtain recurrence years for different engineering purposes can be directly multipledwith the design runoff, which may be obtained with the reference of the rainfall-area-frequency charts and soil conditions for certain areas. A flood hydrograph using an instantaneous unit hydrograph provides a goodappreach for hydrologic research since the short duration of effective rainfall isclose to the duration caused by an instantaneous burst of rainfall. The study alsosynthesizes the parametric hydrograph which simplifies hydrograph analysis.
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