Based On Genetic Algorithm-BP Neural Network Eutrophication On Reservoir

Nowadays the water quality is of gradual shortage, the protection of drinking water is imminent. Eutrophication has become a major global water environment, the global economy maintained rapid growth, has brought increasingly serious problem of environmental pollution. The world's fast economical development has resulted in more and more seriously Environmental pollution problems such as water eutrophication of lakes and reservoir. In the areas of lots of human activities with the eutrophication is speeding up, the water quality is getting so worse and worse that the development of society and economy is limited. Located in Wanning City in Hainan Province, Wanning Reservoir was built in 1959. It provides services of irrigation, the main source of drinking water, power generation, flood control, fish and so on.As the Wanning reservoir basin-wide development activities intensify, a large number of ecological environment of negative issues will inevitably be brought about. Therefore it is particularly important to master of eutrophication and predict it accurately. In this paper, to sum up and learn research results from their predecessors, the following points were mainly studied:â‘ The progress and research methods of the eutrophication is systematically expounded.â‘¡from short-term and long-term forecasts predict the perspective of the establishment of the Wanning reservoir eutrophication forecast management system.â‘¢to accurate and effective early-warning forecast for short-term forecasting, prediction analysis of existing strengths and weaknesses of the model, combining the analysis of the data in front of selecting the optimal model - BP neural networks, genetic algorithms using the BP neural network to be less than that .In this paper, the Wanning reservoir water quality status of the investigations and studies, collection of information are done. Use factor analysis screening and analysis of the information gathered to identify the impact of eutrophication the main factor Reservoir: water temperature, total phosphorus, total nitrogen, dissolved oxygen, chlorophyll a; drawn Wanning Reservoir water quality parameters of the distribution curve, analyzed Eutrophication-made reservoir, analysis of the causes of eutrophication: in Wanning reservoir in recent years nitrogen, phosphorus have been exceeded the standards; serious Wanning reservoir in the tropical oceans of the monsoon climate, the perennial water temperature higher, the light intensity; slow water flow. Analysis of the strengths of the existing prediction model and the lack of analysis of the data in front of selecting the optimal model - BP neural networks, genetic algorithms using the BP neural network to be less than that.Through the mechanism of eutrophication forecast to identify indicators - chlorophyll a, water temperature, total phosphorus, total nitrogen, dissolved oxygen, as a model input, next month as output Chl-a neural network to establish adaptive GABP mathematical model.With Matlab7.0 preparation procedures, use of water years 2000-2005, an average of monitoring data on the model of training for training and found fitting model, the ability to better generalization: neural networks, the 865 study, the error to a default Accuracy of 0.0001, run total time was 36.5770s; fitting and measured the relationship between the coefficient (R) is 0.999.Adaptive GABP model and BP neural network optimized not by adaptive genetic algorithm training results found: adaptive learning rate BP neural network by 27,950 after learning of the error before converging to 0.001857, in addition to a significant amount of time, not accuracy meet the requirements of error of the difference from an order of magnitude.After adaptive GABP model training, forecast by the 2006 years of amended monitoring data: the biggest relative error was -11.4%, only a relative error of absolute value greater than 10 percent, the average relative error of 0.172 percent, Forecast for high precision, the reservoir can be used as the basis for the forecast state of eutrophication.Adaptive GABP use of short-term forecast accuracy, forecast early warning of water quality, after analysis, warning line selected as the concentration of chlorophyll a 0.004 mg / L, exceeding the warning line and the forecast made contingency measures.â‘£Dillon also established a model to study the development trend of nutrients, the medium and long-term TN, TP average concentration in the forecast, Dillon found that although the model no short-term forecast accuracy of high precision, but to meet the trend of the accuracy of forecasts, according to water use Model environmental capacity in the medium and long-term forecast on the basis of Wanning Reservoir TN, TP reduction plan, the final scientific pollution prevention and control measures.