南水北调中线工程典型渠段一维水动力水质模拟与预测

One-dimensional hydrodynamic simulation and water quality prediction of typical channel of the Middle Route of South-to-North Water Diversion Project

为了研究南水北调中线工程复杂水工建筑物影响下的水流特性以及对污染物在渠道内输移、衰减过程的影响,保证输水过程中的水质安全,分析了突发性污染事故潜在污染源特征,构建了南水北调中线工程典型输水渠段的一维水动力水质模型,模拟倒虹吸、节制闸、涵洞、隧洞、渡槽、公路桥6种水工建筑物影响下输水渠道内的水流特性,采用七里庄断面实测水位、流量、水质(总磷、氨氮)数据对模型进行了校核与验证;并运用该模型预测店北公路桥突发水污染事故时,3种输水流量、3种负荷、3种污染物泄露至渠道后污染物沿程分布规律。结果表明:该模型能有效模拟复杂水工建筑物下的水动力和污染物输移特性,下车亭分水口处污染物浓度超标与否受输水流量和污染负荷共同影响。针对分水口处水质指标浓度变化,提出合理、有效分水和退水方式,为保障南水北调中线工程输水水质安全提供参考。

This study aims to explore flow characteristics through complex hydraulic structures in the Middle Route of the South-to-North Water Transfer Project, and how pollutants transport in the channels.A MIKE 11 one-dimensional hydrodynamic and water quality model is established. The model calibration and validation are conducted using measured water levels, discharges, and water quality data(total phosphorus, ammonia nitrogen) at Qilizhuang section. On the basis of hydraulic structures setting over study channel, potential pollution sources for transferred water is analyzed. Dianbei bridge is considered as the location occurred sudden pollution accidents. Total three steady discharges, three pollutants, and three loads of each pollutant are simulated employing this model. Simulation result shows that the model is a good predictor for water flow and pollutants concentration for the study channel. Concentration of pollutants at Xiacheting diversion is affected by the input discharges and pollution loads. And also, reasonable suggestions are proposed to guarantee required water quality for water transfer projects.