Emergency dispatch simulation for sudden water pollution accident in downstream reach of the Three Gorges Reservoir
[Objective]There are many potential water pollution sources in downstream reach of the Three Gorges Reservoir(TGR)that pose a serious threat to the water supply security if a sudden water pollution accident occurred.The TGR has the ca-pacity to carry out emergency dispatch for sudden water pollution accidents,but there are still many challenges for it.In order to clarify the coordination strategy between emergency dispatch and normal dispatch of the TGR,[Methods]firstly,HEC-RAS soft-ware was used to model and analyze the migration rule of heavy metal pollution clouds.Then,the effects of emergency dispatch duration and intervention time of the TGR were investigated.Finally,based on the normal dispatch constraint generalization and above computational and analytical result,the emergency dispatch strategy of the TGR was proposed for different dispatch peri-ods.[Results]Water pollution simulation result showed that:when 20 t hexavalent chromium leak into Yichang River section,the pollutant exceedance time of Yichang to Hankou River section will be 2～3 d at a discharge of 20 000～30 000 m3/s,and 4 d at a discharge of 6 000 m3/s.TGR's emergency dispatch of adding the discharge can shorten the pollutant exceedance time of each intake by 1～4 h,the longer the dispatch duration,the better the effect.A 5-hour advance in emergency dispatch interven-tion time would result in 1～2 h advance in the arrival of the pollution cloud at the water intake.However,both emergency dispatch intervention time and duration have little effect on pollutant concentration.[Results]showed that TGR's emergency dis-patch of adding the discharge can not reduce the pollution concentration,but it can shorten the pollutant exceedance time.[Conclusion]Accordingly,the emergency dispatch of reducing the discharge can control the pollution diffusion range,slow down the propagation speed of the pollution clouds,and create conditions for in-situ disposal.Combined with the above calculation and analysis result,the strategy for emergency dispatch of TGR is proposed on the basis of considering the constraints of normal dis-patch.In the main flood period,emergency dispatch of reducing the discharge is appropriate.In the pre-flood period,emergency dispatch of adding the discharge is appropriate.In the storage and water supply period(except for January-March),emergency dispatch of adding the discharge and reducing the discharge are all appropriate.The research result have reference and guiding significance for the emergency dispatch of the TGR in case of sudden water pollution accidents in the middle and lower reaches of the Yangtze River.
Three Gorges Reservoirsudden water pollution accidentemergency dispatchHEC-RASheavy metal pollutionwater environmentrisk sourcenumerical simulation
万方数据
维普
