Research On Early Warning And Forecasting Water Quality Safety Of The Three Gorges Reservoir Region Under Sudden Water Pollution Accident Conditions

With the rapid development of social economy and the intensification of industrialization,China's water pollution incidents have entered the peak period,which seriously threaten the security of public drinking.Water Quality Safety Early WarningForecasting(QSEWF)has the function of preventing harm in advance,which gains extensive attention from people.The theory and method of the QSEWF are the foundation of the construction model,and also the important ways to ensure the safety of drinking source.Therefore,it has important theoretical and practical significance to establish a security evaluation system of drinking sources,and to elaborate the transmission mechanism of the water source pollution and the reasonable classification of the warning level.The establishment of a more comprehensive and general applicability of the QSEWF model can provide references for the design and construction of QSEWF system,and provide decision support for the management of water resources.The improvement degree of the framework structure of the QSEWF model,the gap between the theoretical method and the actual situation,and the classification of the early warning level directly affect the accuracy,authenticity and scientific nature of the early warning results.At present,there are few researches on the theory and method of the model at home and abroad.Therefore,this article has carried on the research to this problem,the main research contents of which are as follows:1)The basic situation of the Three Gorges Reservoir area was summarized,and the security requirement of drinking water source in the area was clearly defined.The types and causes of sudden water pollution incidents in recent years were analyzed.Water environment risk sources of drinking water source,risk size and formation mechanism were studied.2)Based on the introduction of current research status and development trend of comprehensive evaluation of water quality,this paper analyzed the common methods of comprehensive evaluation of water quality.The method of single factor pollution index,the operation of which was convenient and meets the actual situation of the Three Gorges Reservoir area,which was chosen to carry out the research.Additionally,the safety evaluation index system of water source was established.3)According to the current situation of the water environment in the Three Gorges Reservoir area,the water environment security assessment system was established.Afterwards,the framework of the QSEWF was built.Using water quality model to simulate the pollutants,the model of water quality and safety forecast was established;Due to the powerful calculation and drawing ability of MATLAB,the QSEWF was built.4)The example of Three Gorges Reservoir Area-ZiGui water source containing the total phosphorus was investigated by using the QSEWF model.The simulation results are shown as follows: the polluted area,the length and width of which were about 9,000 m and 1,800 m respectively,was formed after the water pollution accidents happened;the duration of over-standard concentration was 60 h in original point of accidents;it could be found that the decreasing range of contaminant concentration changed greatly when the flow velocity increased.