Identifying Dominant Discharge for River-type Reservoir Channel Based on Dynamic Sediment Transport Capacity Method

基於動態輸沙能力法確定庫區河道造床流量

10.6937/TWC.202103/PP_69(1).0005

陳鵬(Peng Chen)；談廣鳴(Guangming Tan)；鄧金運(Jinyun Deng)；許全喜(Quanxi Xu)；湯柔馨(Rouxin Tang)；馮志勇(Zhiyong Feng)

Reservoir channel ； Dominant discharge ； Dynamic sediment transport capacity method ； Incoming water and sediment ； Reservoir operation ； 庫區河道 ； 造床流量 ； 動態輸沙能力法 ； 來水來沙 ； 水庫調度

台灣水利

69卷1期（2021 / 03 / 01）

67 - 80

英文

Dominant discharge is considered as a discharge that plays the biggest role in shaping river bed morphology, it is an important parameter reflecting the process of incoming water and sediment as well as channel morphology. At present, most of the relevant research methods are proposed for alluvial rivers, and the determination method of dominant discharge in reservoir channel is relatively few. On the basis of comparative analysis of various methods for determining the dominant discharge in alluvial rivers, a new method for calculating the dominant discharge in reservoir channel is proposed in this paper, and the validation is carried out by using the measured water and sediment along with topographic data at Qingxichang and Wanxian hydrological stations in the Three Gorges Reservoir area of the Yangtze River from 1981 to 2017. The results show that: (1) Various methods suitable for determining the dominant discharge in alluvial rivers are not suitable for river study in reservoir channel. (2) Based on dynamic sediment transport capacity method, the calculation of dominant discharge in reservoir channel is not only clear in physical meaning and reasonable in results, but also feasible in topographic verification, which can be better applied to the determination of dominant discharge in reservoir channel. (3) The dominant discharge is not a single process of incoming water or incoming sediment in reservoir channel, the influence is also related to the reservoir operation mode during the bed-forming period. Before the impoundment of TGR, the correlation between dominant discharge and incoming water amount is closer than that of incoming sediment amount, which reflects that the bed-forming effect is mainly determined by incoming water, and the influence of incoming sediment on bed-forming effect is relatively small; after the impoundment of TGR, the correlation between dominant discharge and incoming water along with incoming sediment are not obvious. The research in this paper can provide reference for the determination of dominant discharge in reservoir channel, and provide scientific technical parameters for river management.

造床流量是對塑造河床形態起到最大作用的特徵流量，是反映來水來沙過程和河槽形態的重要參數。目前相關研究方法大多是針對沖積性河道提出，關於庫區河道造床流量方法的研究相對較少。本文在對比分析各種沖積性河道造床流量確定方法的基礎上，提出了一種應用於庫區河道的造床流量計算方法，並採用長江三峽庫區河段清溪場和萬縣兩座水文站1981－2017年實測水沙及地形資料進行驗證。結果表明：（1）適用於沖積性河道造床流量的各種方法不適用庫區河道研究。（2）基於動態輸沙能力法的庫區河道造床流量計算不僅物理意義明確、結果合理，而且地形驗證可行，可較好適用于庫區河道造床流量的確定。（3）庫區河道造床流量並不單一受來水（來沙）過程的影響，同時也與造床期時水庫調度方式有一定關係。蓄水前，造床流量與來水量相關性相對于來沙量更為緊密，河道造床作用主要由來水量決定，來沙量對造床作用的影響相對較小；蓄水後，造床流量和來水來沙量相關性均不明顯。本文的研究可為庫區河道造床流量的確定提供參考，以及庫區河道管理提供科學的技術參數。

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