长江重庆主城区段突发水污染事故模拟研究

因重庆山城特殊的地势，主城区沿长江和嘉陵江两岸建有多种形式的排水干管，一旦发生管道破裂将危及下游水厂取水口的水质安全。在三峡水库蓄水至175 m水位后，针对长江重庆主城区段可能发生的突发水污染事故，基于实测地形、水文等数据，构建二维水动力水质耦合模型，采用优化反演法率定河道糙率，借助有限元法分别模拟河流在丰、枯水期管道破裂事故发生后在24 h或48 h完全修复的情况下，各类污染物（五日生化需氧量BOD₅、化学需氧量COD、总氮TN、总磷TP）质量浓度随时间和空间的变化。模拟结果可为重庆主城突发排水干管破裂的应急预案优化提供科学依据。

Simulation of an emergent water pollution accident in the portion of the Yangtze River running through the main urban areas of Chongqing

Due to the special terrain of Chongqing City, various types of drainage trunks have been built along the Yangtze River and the Jialing River. Once a pipeline bursts, it will endanger the water quality of downstream water intake. Aiming at the establishment of a management system for sudden water pollution risk that may occur in the Chongqing Section of the Yangtze River after the impoundment of the Three Gorges Reservoir up to 175 m, a two-dimensional hydrodynamic water quality coupling model was built based on the measured topographic and hydrological data, and optimal inversion method was used to determine the roughness. The finite element method was applied to simulating the temporal and spatial variations of pollutant concentrations including the five-day biochemical oxygen demand (BOD₅), the chemical oxygen demand (COD), the total nitrogen (TN), and the total phosphorus (TP) under the condition that the fractured pipeline be completely repaired after 24 h or 48 h in the high and low water periods. The simulation results can provide a scientific basis for the optimization of the emergency plan in case of a sudden drain pipe rupture in Chongqing.