基于SMS模型的临沂城区河流水流水质模拟研究

Simulation of water quality in the urban rivers of Linyi based on SMS model

随着临沂市辖区小流域污染综合控制措施和河道治理工程的实施,临沂城区的水体环境与河道生态景观效果不断提升,但水体富营养化形势依然严峻.基于SMS模型建立了临沂城区河流二维水流水质数学模型,通过计算边界简化、网格划分与检验、参数选取与水文调查等研究工作,确定了各计算方案的水力学和水质边界条件,模拟了小埠东橡胶坝东、西端调节闸单独泄流时,临沂城区河流的二维流场和氮磷浓度场.结果表明:东、西端调节闸单独泄流时,流速随着离泄流口距离的减小而增大,在东、西端泄流口处流速达到最大,分别为0.10、0.12m/s;城区河流水体富营养化与泄流口选择没有直接关系;2017年5月水质现状氮磷比在20～55之间,实测最大浓度时水质氮磷比在20左右,与水质标准限值时水质氮磷比在5～7之间相比,发生水体富营养化的风险较高.因此,制定和实施临沂城区水体氮磷控制削减方案迫在眉睫.

With the implementation of comprehensive pollution control measures and river regulation project in the small watershed of Linyi District,the effects of water environment and river ecological landscape in Linyi City have been continuously improved,while the water eutrophication situation is still severe.Based on the SMS model,a mathematical model for two-dimensional flow water quality of Linyi urban river was established.Through the calculation of boundary simplification,grid division and test,parameter selection and hydrology investigation,the hydraulic and water quality boundary conditions of each calculation scheme were determined.It simulated the two-dimensional flow field and nitrogen and phosphorus concentration field in the urban area of Linyi when the regulating sluice in the east and west ends of Xiaobudong Rubber Dam is discharged separately.The results show that when the regulating sluice is vented separately at the east and west ends,the flow velocity increases with the decreasing distance from the discharging orifice.The flow velocity at the outlet at the east and west ends reaches its maximum,which are 0.10 and 0.12 m/s respectively;There is no direct relationship between the eutrophication of rivers in urban areas and the selection of discharging gate.The N/P ratio of water quality in May 2017 is between 20 and 55.N/P at the measured maximum concentration is about 20.Risk of eutrophication is higher when compared with N/P 5~7 at the standard water quality.Therefore,it is urgent to formulate and implement the reduction plan of nitrogen and phosphorus in the water body of Linyi City.