Author(s): Dechao Hu; Jie Zhang; Zhanfeng Cui; Deyu Zhong
Linked Author(s):
Keywords: Three-dimensional; Numerical model; Circulation extraction; Circulation intensity; Three Gorges Project (TGP); The Jingjiang River
Abstract: The operation of the TGP leads to new inflow and sediment boundary conditions for the downstream Jingjiang River in the middle Yangtze River. The river has been experiencing significant riverbed degradation since 2003, and its 3D flow properties are also changed. The method in paperⅠis used to study circulation properties of the Jingjiang River. Three typical river reach are focused, which are the Shashi reach (25km) in the upper Jingjiang River, the Jianli reach (15. 5km) and BxIsland reach (78km) in the lower Jingjiang River. Based on 3D numerical simulations on the 2002 and a recent (2009 or 2010) topographies, the circulations at cross-sections along the river are extracted and compared. It is concluded that the circulation intensity (II) at middle parts of the Shashi, Jianli and BxIsland riverbends are all reduced during the early operation of the TGP. The relative reductions of II are 3. 30% , 4. 85% and 6. 03% in turn. Then, a piecewise, parabolic theoretical model is proposed to describe the circulation variation along a riverbend. It is interesting to found that the circulation variation amplitude ratios of the latter part to the former part of a riverbend just approximate to a constant (≈2. 2).
Year: 2013