Channel bifurcation in braided rivers: Equilibrium configurations and stability

被引:150
|
作者
Bolla Pittaluga, M [1 ]
Repetto, R
Tubino, M
机构
[1] Univ Genoa, Dipartimento Ingn Ambientale, Genoa, Italy
[2] Univ Aquila, Dipartimento Ingn Strutture Acque & Terreno, I-67100 Laquila, Italy
[3] Univ Trent, Dipartimento Ingn Civile & Ambientale, Trento, Italy
关键词
bifurcation; braiding; stability;
D O I
10.1029/2001WR001112
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
[1] We investigate the equilibrium configurations and the stability of river bifurcations in gravel braided networks. Within the context of a one-dimensional approach, the nodal point conditions play a crucial rule, as pointed out by Wang et al. [1995] who propose an empirical relationship relating water and sediment flow rates into the downstream branches. In the present paper, an alternative formulation of nodal point conditions is proposed based on a quasi two-dimensional approach. The results show that, if the Shields parameter of the upstream channel is large enough, the system only admits of one solution with both branches open, which is invariably stable. As the Shields parameter of the upstream channel decreases, two further stable solutions appear characterized by a different partition of water discharge into the downstream branches: in this case, the previous solution becomes unstable. Theoretical findings are confirmed by the numerical solution of the nonlinear one-dimensional equations.
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页数:13
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