基于EFDC模型的汤河水库污染物质扩散模拟

Simulation of Pollutant Diffusion in Tanghe Reservoir Based on EFDC Model

目的 模拟水库区域可能发生的累积性污染物质及突发风险事故泄露的污染物质在水中的扩散,预防水源地危险事件发生,保证居民饮水安全。方法 基于汤河水库已有数据及实测水文水质数据建立EFDC模型,并对汤河水库的水体状态进行动态模拟,验证模型的可行性。基于EFDC模型建立库区水动力水质模型,分析针对性模拟污染物在典型年的扩散情况。结果 对TP和NH_(3)-N进行6个月模拟,丰水年对出水水质影响较大,会造成出库水水质超过地表水Ⅱ类标准;枯水年对出水水质影响较小,6个月后TP和NH_(3)-N超标水质距离水库出水口分别为6 960 m和7 600 m;平水年6个月后TP和NH_(3)-N超标水质距离水库出水口分别为1 700 m和3 850 m。对污染物质泄漏情况模拟,事故发生0.25 d污染物扩线极快,在2 d后迁移速度逐渐下降,5 d后污染物迁移600 m,当突发性风险事故发生后94 d时,扩散至水库出水口,但出水口最高污染物质量浓度低于0.000 3 mg/L.结论 建立的EFDC模型对污染物质可以进行有效地模拟,扩散的污染物质会长期影响水库水质,因此需及时对污染物质进行处理,避免对城市供水产生影响。

In order to ensure the safety of drinking water sources,the possible cumulative pollutants and the pollutants leaked by sudden risk accidents in the reservoir area was simulated.Tanghe reservoir in Liaoning province as sample,an EFDC model was established based on the existing data of Tanghe reservoir and the measured hydrological and water quality data.The water environment of the Tanghe reservoir was simulated and the model was verified.Based on the EFDC model,a hydrodynamic water quality model was established to simulate the pollutant diffusion in a typical year.The diffusion process of TP and NH_(3)-N was simulated for 6 months.The results showed that the influence of high flow water year on the effluent quality was more obvious.It will cause the outlet water quality of reservoir to exceed the class II standard of surface water.In low flow year,the point of TP and NH_(3)-N exceeding class II water quality are 6 960 m and 7 600 m away from the reservoir outlet after 6 months,and in normal flow year,are 1 700 m and 3850 m.The diffusion process of pollutants leakage caused by sudden risk accidents in high flow year in reservoir was simulated.The results showed that the pollutant line expansion is fast in 0.25 days after the accident,and the migration speed gradually decreases in 2 days.The pollutant migration is 600 m in 5 days.After the sudden risk accident 94 days,the contamination spread to the reservoir outlet,but the maximum concentration at the outlet is less than 0.000 3 mg/L.The EFDC model can simulate the pollutant diffusion effectively.The diffused pollutant will affect the water quality of the reservoir for a long time,so it is necessary to treat the pollutant in time to avoid the influence on the urban water supply.