圖書典藏及影音數位平台

本計畫係藉由與國內外著名之輸砂學者合作，以臺灣河川泥砂運移特性為案例，擴充建置本土化輸砂公式，並結合現有數值模式，以臺灣5大流域為案例進行河道穩定與流域土砂運移與管理研究。整體工作架構包括臺灣河川基本資料現地補充調查、國際合作研發本土化輸砂公式、及本土化輸砂公式結合數值模式進行應用研究等三大部分。

Steep slope, severe bed change and young geologic texture are the characteristics of Taiwan’s rivers. These characteristics often case huge sediment transport rate, and the foreign common sediment transport formulas have the limits to apply in Taiwan’s river. This study spends three years to develop a new sediment transport formula which is suitable for the characteristics of Taiwan’s rivers. The flow and sediment data are surveyed and collected during the floods. These measured data are used to develop two new sediment transport formulas, which are installed in the numerical model, SRH-1D. Two approaches are used to develop the new formulas. The first approach uses the three formulas selected by the review of foreign common formulas, and recalibrates their coefficients using the collected data. The best performance one is the final formula to be used. The second approach uses the basic theories of sediment transport, including Bagnold’s stream power, Yang’s minimum stream power, diffusion theory, and gravitational theory to develop a local formula. According to the formula of Wu et al. (2000), the bed-load transport rate is highly related to grain shear stress, and the suspended-load transport rate is highly related to the stream power available in the flow system. In addition, the hiding and exposure mechanism in the nonuniform bed material significantly affect sediment transport and should be taken into account. After series of comparisons with the results of numerical simulations, the formula of Wu et al. (2000) modified by Yeh et al. (2017) has the best performance in Dajia River, Choushui River and Kaoping River.