洋河-戴河河口海域COD时空分布特征研究

首先应用MIKE 21软件建立了洋河-戴河河口海岸水域水动力与污染物输运数学模型,然后采用实测潮流和化学需氧量(COD)浓度对数学模型进行了验证,最后模拟分析了河口海岸水域COD的输运过程.结果表明,洋河-戴河近岸海域潮波为驻波;潮流为顺岸往复流,涨潮流方向为NE向SW,落潮流方向为SW向NE.涨、落急时刻,河口至外海水域潮流流速递增.COD输运方向与涨落潮潮流方向一致.涨憩时刻,COD高浓度区向河道推进,其面积最小;落憩时刻,COD高浓度区向外海推进,其面积最大;葡萄岛周围潮流流速低,在潮周期内小于0.14m/s,对COD的稀释作用较弱.

Study on spatial and temporal characteristics of the COD in estuarine and coastal waters of the Yanghe River and the Daihe River

Based on MIKE 21 software, a hydrodynamic and pollutant transport model has firstly been established for the estuarine and coastal waters in the Yanghe River and the Daihe River. Then the model is verified by measured tidal current and concentration of Chemical Oxygen Demand (COD). Finally, the transport processes of COD in the estuarine and coastal waters are simulated and analyzed. Numerical results show that the tidal current in the coastal water of the Yanghe River and the Daihe River can be characterized as a reciprocating flow along the shore while the tide is a standing wave. The directions of flood and ebb currents are NE to SW and SW to NE, respectively. The tidal current velocities increase from estuaries to the offshore in both flood and ebb periods. The direction of COD transport is consistent with that of the tidal current. The high concentration region of COD is pushed towards rivers at the slack of flood with the smallest area, while towards offshore at the slack of ebb with the largest area. The tidal current velocity is quite small in the region around the Putao Island, generally less than 0.14m/s in a tidal cycle, which leads to weak dilution of COD.