| Taipu River is located in the upper reaches of Huangpu River.Besides flood control,drainage and shipping functions,it also serves as a water supply for Pinghu,Jiashan in Zhejiang and five southwest districts of Shanghai.With the development of cities,the contradiction between economic development and water source protection has become increasingly prominent.106 water pollution incidents have occurred since 1998-2015,among which 74 incidents were oil pollution incidents,accounting for 69.8%.Since Jinze Reservoir operated in 2016,we tracked and monitored the oil pollutants along Taipu River and found that the oil concentration exceeding the standard rate was 62.96%.It can be seen that oil pollution has become one of the most important pollutions in Taipu River,and ships,docks,gas stations and industrial enterprises pose potential threats to the security of Taipu River water source.Therefore,the oil pollution risk assessment and oil pollution simulation of Taipu River are conducive to reducing the ecological and economic losses caused by possible oil pollution accidents in the future,and the related achievements can provide scientific reference and technical support for the risk management and control of oil pollution in the basin.This paper collected and sorted out the situation of oil pollution accidents at home and abroad,and made an objective,systematic and quantitative analysis of the time change rules,accident causes and pollutant types of oil pollution accidents by using data statistical analysis method,and summarized the characteristics and rules of oil pollution accidents.Based on the investigation of oil pollution accidents in Taipu River,this paper constructed the characteristic frame of oil pollution accidents by the analysis of accident tree,and analyzed the characteristics of oil pollution accidents.On the basis of the characteristic analysis,the paper analyzed the change rules of oil pollution concentration in time and space in Taipu River by using Spearman correlation and systematic clustering method according to the annual water quality monitoring results of Taipu River.Based on the "Risk Prediction Theory" before the accident,this paper identified the risk sources of oil pollution in Taipu River and carried out traceability analysis from the perspectives of mobile risk sources and stationary risk sources,exploring the relationship between the number of ships,spatial distribution characteristics of stationary sources and oil concentration.Based on the MIKE11 hydrodynamic model and the OILMAP model,the pollution contribution rates of mobile risk sources and stationary risk sources under normal conditions were calculated and the oil spill simulation of sudden oil pollution accidents was conducted.The main research conclusions and results obtained in this paper are mainly divided into the following three aspects:(1)Study on the characteristics and the laws of temporal and spatial changes of oil pollution in Taipu RiverBased on the accident tree analysis,the characteristics of oil pollution accidents of Taipu River were studied.It was found that the main causes of Taipu River oil pollution include ship collision leakage,vehicle fire and explosion leakage,wharf explosion fire and gas station explosion fire,etc.According to the annual monitoring results of oil pollutants in Taipu River,it was found that the annual monitoring point concentration at the water intake of jinze reservoir exceeds the standard,and the oil pollutant exceeding rate reaches 62.96%.The spatial clustering results showed that the concentration of oil pollutants in the middle and upper reaches was low due to the inflow from the east Taihu Lake,while the concentration of the middle and lower reaches section and the monitoring point of the reservoir was high due to the inflow from the beijing-hangzhou canal,which exceeded the three water standards and seriously threatened the safety of the water source.(2)Taipu River risk source identification and traceability analysis resultsThe identified risk sources of Taipu River are ship risk,vehicle risk,riparian wharf,gas station and industrial enterprise.According to the risk source identification results,traceability analysis was carried out.Three monitoring sections,namely,the upstream Meiyan Bridge,the middle Fenhu Bridge and the downstream Dongcai Bridge,were selected to carry out all-day observation of ship flow sources in summer and autumn,which lasted 50 hours and collected 2,320 ship information.Through observation,it was found that the ship flow was about 1,160 ships per day.And there is a significant positive correlation between the number of ships and oil concentration.The results of stationary source analysis showed that the change of oil concentration was characterized by the change from top to bottom along the Taipu River.The change of concentration tended to increase first and then decrease.The concentration of pollutants in the upstream water was the lowest,and the oil concentration in Fenhu which is in the middle reaches was the highest.The spatial concentration of stationary source is positively correlated with oil concentration.Therefore,the current stationary risk sources pose a great threat to the water source,and are easy to cause pollution to the water quality of the water source.(3)Simulation results of sudden oil pollution accidents and normal oil emissionsIn the simulation of sudden oil pollution accident,under the setting of adverse conditions,when 10 t diesel oil leakage occurs at the Fenhu Bridge which is 7.2km away from the water intake,the oil will reach the intake of Jinze reservoir in about 4.1 hours.When a 10 t diesel oil leakage occurs at the Dongcai Bridge,which is 1.3km away from the water intake,the oil will reach the water intake of Jinze reservoir in about 0.4 hours.The oil pollution continue to affect the water quality of the water intake of Jinze reservoir after reaching the water intake.Under normal conditions,the oil pollution emission simulation shows that the contribution of oil pollutants from mobile sources is about 3.3 times of that from stationary sources.With the increase of discharged flow under Taipu sluice,the contribution rate of oil pollution from upstream also increases,while the contribution of mobile sources and stationary sources decreases with the increase of discharged flow under Taipu sluice.The model simulation confirmed the risk of oil spill accident,provided the key direction for regional response measures,and put forward the response measures for Taipu River oil pollution according to the simulation situation,and provided the theoretical basis and technical support for the region to take effective emergency response measures. |
PDF Full Text Request