白洋淀典型示范区围埝对连通性影响的研究

Study on the influence of cofferdam on hydraulic connection in Baiyangdian typical demonstration area

连通性是水体生态环境及防洪排涝的重要影响因素,为探究围埝的拆除对于白洋淀水力连通效果提升的影响,以白洋淀南刘庄典型示范区为研究对象,利用MIKE21软件构建二维水动力模型。通过对该区域5种方案的模拟,分析拆除区域的水位变化、流场流速及流速区分布,进而确定了围埝的最佳拆除高度与拆除顺序。结果表明,将围埝拆除至淀底高程时,流速由原来的2 mm/s提升至4.6 mm/s,且滞水区面积减少77.8%,连通性提升最为显著;优先拆除顺水流方向围埝对区域水体扰动最小。由此可知,围埝拆除工程对提升淀泊水动力有积极作用,此次模拟对类似生境修复的工程体系具有一定的借鉴意义。

Connectivity is an important factor affecting water ecological environment,flood control and drainage.In order to explore the influence of the cofferdam demolition on the improvement of the hydraulic connectivity effect of Baiyangdian Lake,this research takes the typical demonstration area of Baiyangdian Nanliuzhuang as the research object,and uses MIKE21 software to build a two-dimensional hydrodynamic model.Through the simulation of five schemes in this area,the water level distribution,flow velocity and velocity distribution in the demolished area were analyzed,and the optimal removal height and removal sequence were determined.The results showed that when the cofferdam was demolished to the lake bottom elevation,the velocity increased from 2 mm/s to 4.6 mm/s,the stagnant area decreased by 77.8%,and the connectivity improvement was the most significant;the priority of removing the cofferdam along the flow direction had the least disturbance effect to the regional water body.Therefore,the dam demolition project has a positive effect on improving the hydrodynamic force of the lake.This simulation has the reference significance for similar ecological restoration engineering system.