JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 H (地球人間圏科学) » H-CG 地球人間圏科学複合領域・一般

[H-CG28] [EE] デルタ(三角州):複雑系への学際的アプローチ

2017年5月24日(水) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:斎藤 文紀(国立研究開発法人産業技術総合研究所地質情報研究部門)、Paola Passalacqua(University of Texas at Austin)、堀 和明(名古屋大学環境学研究科地理学講座)、Efi Foufoula-Georgiou(University of Minnesota)

[HCG28-P03] Numerical model for the growth of distributary channel bifurcation on river delta

*Wun-Tao Ke1John Shaw1 (1.University of Arkansas)

キーワード:channel networks, channel bifurcation, river delta

We propose a numerical model to describe the growth of distributary channel networks on river deltas. The model uses the Laplace equation to describe shallow, unchannelized flow on the delta front and a moving boundary to describe the evolving channel network. The boundary element method is applied to solve the Laplace equation to obtain the outflow flux on the distributary boundary. Movement of the channel network boundary (u = (ux,uy)) is a function of the outflow flux along the boundary (q). The relation u ~ qα with α=1.5-2.5 is consistent with common sediment transport formulae. The model produces emergent channel bifurcations which are similar to processes observed at the prograding Wax Lake Delta, Louisiana, USA. Furthermore, as α increases, the emergent width of distributary channels is reduced. Further comparisons with experiments and field data will be used to validate the numerical results. The model provides a new tool for investigating channel spacing and bifurcation dynamics in complex distributary channel networks.