Study On Quality Evaluation And Prediction Model Of Typical Gradually Changeable Water

At present, the effective technology system for quality monitoring and warninghas not built in china, and the water quality warning technology need to be establishedurgently at all levels from national to regional. In order to control water qualitydeterioration greatly, the most effective method is taking preventive measures. Beforethe occurrence of water quality deterioration, the forenotice and warning are madeearly and the measures are took as soon as possible, which is to suppress, mitigate andcontrol the water quality deterioration, and make it into a healthy circulation.Recent years，Jinan city takes measures of yellow river diversion to protectsprings and supply water, the reservoir plays an important role in development ofeconomy and society in Jinan city, the survey showed that the water quality in thereservoir appeared gradualness. Based on the gradualness of the water quality, andcombining with the mature evaluation method for water quality and themulti-functional time series model, the study built the evaluation and warning systemof water quality with Java language, and used the system in actual projection fordecision-making and supporting.Firstly, five methods were used to evaluated the water quality of queshanreservoir, including single factor index, nemerow index, comprehensive mark index,fuzzy comprehensive evaluation and grey relational analysis method. According to thecalculation results and analysis, the difference of evaluation results was smalleramong the comprehensive mark index, the nemerow index and fuzzy comprehensiveevaluation, and the results were scientific and rational. Comparing with the evaluationresults of these three methods, the comprehensive mark index method was closer tothe practical water quality. The comprehensive mark index method was selected andused to evaluate the water quality of gradually changeable water finally. Theevaluation results showed that the water quality of Queshan reservoir could overallmeet the water quality standards of grade Ⅲ, and was in line with water qualitystandards of centralized drinking water source. Secondly, according to the changingcharacteristics of the water quality, and based on the time series model and Javalanguage, the paper studied the origin, obtaining and conversion of the water qualityattribute date and graphic data, constructed organizational pattern and structure of thesystem database, and built the connection and two-way update mechanism betweenattribute date and graphic data. Also, with the powerful data management and thetopological relation analysis function of Java platform, the study extracted the waterdata used in water quality model, completed the water quality prediction and analysisof the water quality model, and developed the accurate, science, and efficient waterquality prediction system. Finally, the system was used in Queshan reservoir. The study made the water quality data of2010as a reference, predicted the change ofwater quality and compared the real value with the predictive value of the systemthrough selection of water quality parameters, database creation and a series of steps.The results showed that the simulation errors of the system were small, calibrationresults were better, the goodness of fit was higher between the calculated values andthe predicted values of water temperature and dissolved oxygen, and the calculatedvalues of Nutrients were consistent with the actual situation basically, which couldmeet the requirements of the water quality model, and fully demonstrated that thesystem could be used in daily management and water quality prediction of thereservoir, and provide early warning for water quality safety.