钱塘江河口段潮动力对污染物稀释扩散作用探讨

Analysis on tidal-driven dilution and transportation of contaminants in Qiantang estuary

本文采用了平面二维有限元数学模型模拟计算了钱塘江河口段的潮汐和潮流场,并建立了二维水质模型,分别在大、小潮情况下对该地区污染物的稀释扩散进行了计算。在此基础上,分析比较了在潮动力条件不同的大潮和小潮情况下污染物稀释扩散情况,发现在排放口附近区域浓度增量在大潮时较低,体现了大潮较强的稀释能力;在远离排放口的区域在大潮时的浓度增量则较高,说明更多的污染物在大潮时被挟带到了更远的地区。

In this paper, the tide and current field in Qiantang estuary are simulated by a 2D mathematic model. Moreover, a water quality mode in this estuary is established to simulate the dilution and transportation of contaminants in spring and neap tides separately. Based on this, the dilution and transportation situation of contaminants is analyzed in different tidal dynamic conditions of spring and neap tides. The simulated results illustrate that the concentration increment near the outlet in spring tides is less than that in neap tides because of the superior dilution ability of the spring tides, the concentration increment in the area far away from the outlet in spring tides is more than that in neap tides, it indicates that more contaminants are carried out to farther area because of the better transportation ability of spring tides.