The Quality Evaluation Of The Water Environment And The Study On The Prediction Method In Haihe River Basin

With the rapid development of social economy,the constant expanding scale of human production,the indiscriminate discharge of industrial,agricultural and domestic sewage,the physical and chemical changes of the surrounding water environment are caused by the discharge of large quantities of harmful substances into the water.The evaluation about Water quality is the basic work of preventing and controlling water pollution,planning and governing water environment.To evaluate the water environment in the region with reasonable water quality evaluation method,analyzing the trend of water quality according to the evaluation results,in view of the existing problems of water environment in the current watershed,the corresponding protection measures are put forward to improve the water environment,We will provide strong guarantee for the sustainable development of water resources.The Haihe river basin is one of the seven rivers in our country including all or parts of the region of Tianjin,Beijing,Hebei,Shanxi,Shandong,Henan,Inner Mongolia and Liaoning,a total of 8 state or provinces and autonomous regions.The basin covers an area of 318,000 square kilometers,with about 150 million people living here.In recent years,the pollution surrounded the Haihe river basin was intensified,the water quality declined severely,and the eutrophication was more serious than before.Based on the Haihe River Basin,this paper selected water quality monitoring data of seven evaluation sections included Chao River(the entrance of Miyun reservoir),Yongding River(the export of Guanting reservoir),Haihe River(estuary),Li River(the entrance of Yuqiao reservoir),the Yanghe River(the entrance of Guanting reservoir),Gangnan Reservoir(the main reservoir)and Wei River(the juncture of Henan,Hebei and Shandong)during 2013 to 2015.Then the paper established the water quality evaluation model by using fuzzy synthetic evaluation method,calculated the weight of each evaluation index by using entropy value measure.Moreover,this paper established the set of weight and evaluated the water quality of each section.The results of the evaluation indicated that the main contaminants in several monitoring sections of the Haihe river basin are ammonia nitrogen,and the results obtained by this method are consistent with the actual monitoring results basically.At the present stage,It's necessary to control the pollution in the basin effectively,and prevent the intensification and deterioration of eutrophication.The water quality prediction model based on neural network was adopted to predict the water quality in Haihe river basin,and selected the monitoring data from April to July 2013 as the sample data.Then compared the variation trend of the main pollution factors waspredicted with the measured values,identified the practicability of this method in Haihe river basin prediction,and provided the scientific basis for the management and prevention of water pollution in Haihe river basin.Through understanding the pollution status of Haihe river basin and finding out the overall water quality,it can help the decision makers to provide a reliable scientific basis for environmental planning and management for Haihe river basin.Predicting the changing trend of water quality with the model which based on neural network,it is necessary to make people fully aware of the severity of the problem of water quality deterioration in Haihe river basin and the protection and restoration of water environment.