走马塘拓浚工程的生态效应

根据走马塘拓浚工程实施前后的地形变化,建立拓浚河道平面二维水动力数学模型,模拟河道拓浚前后走马塘典型河段的水动力变化情况,并分析拓浚工程对河道水动力特征的影响和拓浚工程的水生态效应。结果表明,拓浚工程的实施使得区域流速及断面横向流速分布变得均匀,对水环境改善有一定的正效应;河道拓浚工程的实施,短期内有利于浮游植物生长,但对浮游动物的生长有一定抑制作用,而从长期影响结果趋势来看,拓浚工程有利于水生生境系统的恢复与重建;河道拓浚工程的实施有利于底泥质量的改善,减少底泥污染物的含量,减少河道内源释放,对水质改善有正面效应;拓浚工程对底栖生物生境具有严重影响,但是随着时间的推移,底栖生境将会重建。

Ecological effect of dredging engineering in Zoumatang River

According to the changes of the topography before and after the dredging in the Zoumatang River,a twodimensional hydrodynamic model of the river was built to simulate hydrodynamic changes before and after the dredging in typical river sections.The impact of the dredging on hydrodynamic characteristics and the ecological effect of the dredging engineering were analyzed.The results show that,after the dredging,the velocity distributions of the whole area and typical cross-sections became uniform,which had a positive effect on the water quality and aquatic environment.The dredging was conducive to phytoplankton growth within a short period,but it inhibited the growth of zooplankton.According to the long-term trend analysis,the dredging will be conducive to the restoration and reconstruction of aquatic habitat.The dredging can also improve the sediment quality and reduce sediment contaminants and endogenous release.It has a positive effect on water quality improvement and a significant impact on the benthic habitat over a short time,but,as time goes by,the benthic habitat will be reconstructed.