丁坝间距对改善水生生物栖息地作用的数值模拟研究

用于航道整治的丁坝在发挥束水攻沙整治作用的同时，也会因丁坝影响范围内的水沙结构和河床形态改变而造成水生生物栖息地的适宜性变化。常用的水生生物栖息地模拟模型（River2D）因缺乏泥沙（推移质和悬移质）运动和河床变化模块，难以直接用来评价丁坝对栖息地的影响。为此，本文以岷江支流锦江穿过成都华阳镇河段为研究对象，采用水沙耦合的二维浅水模型，结合河道内流量增加法（IFIM）构建栖息地模拟模型。分析双丁坝在不同间距时，河道水沙运动结构、水生生物栖息地适宜性指数分布（HSI）和栖息地加权可用面积（WUA）的变化规律；同时从模拟成果中进一步得到能使WUA值有所提升的最佳丁坝间距，为航道建设河道或生态修复提供一定借鉴。

Numerical simulation study of effects of groin spacing on physical habitat improvement

Spur dikes applied to channel regulation had its own effect on sand scouring and flow contraction. The spur dike, meanwhile, has changed the habitat of aquatic owing to changes in water and sediment structure along with channel morphology of surrounding streamway. However, normal simulation model of aquatic habitat (River2D) due to lack of sediment movement and river bed variation module, cannot be directly used to evaluate the effects of spur dikes on habitat. Thus, this study takes the Min-jiang River tributary of the Jin-jiang river through Hua-yang town of Chengdu city as a case study, use two - dimensional shallow water model coupled with water and sediment, combined with Instream Flow Incremental Methodology (IFIM) are provided to simulate the variations of aquatic habitat. Analysis of double groins in different space, the change rules of the structure of water and sediment movement, the aquatic Habitat Suitability Indices (HSI) and Weighted Usable Area of habitat (WUA); at the same time, the optimal spur distance which can improve the value of WUA is obtained from the simulation results, and make certain recommendations for the channel construction or ecological restoration.