天然河流弯道不同生态治理方案的数值模拟研究

针对鲁北平原区天然河道污染、河道冲淤损坏严重的现状,结合流域河道生态综合整治工程,选用MIKE21软件,建立基于非正交网格的平原区天然河流弯道二维水动力数值模型,模拟天然河流弯道纵横向的流速及水面线特征分布,绘制弯道流速矢量场,得出天然河流弯道的河床及河岸边坡冲刷、落淤分布符合实际情况;结合土壤生物工程技术,提出四种生态治理方案并进行数值模拟,引入鲤鱼流速适宜指数法对治理方案的生态效果进行评价。结果表明,方案4中水流流速趋于均匀分布,对弯道生态治理效果最为显著,生态丁坝在弯道生态治理中起到重要作用。

Research on Numerical Simulation of Different Ecological Treatment Schemes for Natural River Bend

According to the status of serious damage and impact of natural river in the plain and river pollution, combined with the river ecological rehabilitation project, software MIKE21 was used to establish two-dimensional hydrodynamic model of river bend in plain region based on non-orthogonal mesh. And the distribution of velocity of longitudinal and lateral and water surface profile of natural river bend were simulated. Then the flow velocity vector field was plotted to obtain the distribution of scour and fall of the river bed. The bank slope conforms to the actual situation. Combined with soil biological engineering technology, four kinds of ecological control schemes were proposed and the numerical simulation was carried out. The velocity suitability index method was introduced to evaluate the ecological effect of the treatment plan. The results show that the flow velocity in scheme 4 tends to be uniformly distributed, and it has the remarkable effect on the ecological treatment of river bend. The ecological spur dike plays an important role in ecological treatment of river bend.