Groundwater Quality Prediction And Evaluation Model Of Shizuishan Of Ningxia

Shizuishan of Ningxia is seated in arid area, whose imbalance between supply and demand of water resources is very conspicuous, and groundwater is one of its main water sources. Protecting groundwater sources is important for local society and economic development, aiming at the actural change process of the city groundwater quality, this thesis does underground water quality prediction and evaluation research, and its results have important realistic value for reasonable development, utilizing and protection of groundwater resources.Because of fewer monitoring datas of groundwater quality in Shizuishan, the thesis applies many kinds of methods to predict water quality variety tendency of groundwater. First, Based on the observation datas of groundwater quality , it sets up groundwater water quadratic exponential smoothing model. Smooth parameter adopts the following signal and chooses the method adaptively, which solved the smooth parameter perfectly. Then gray system prediction model is made some progress, and an adaptive prediction model with varied parameter is established. According to needs , choosing different parameter values, and calculating the parameter values with minimum error, this thesis sets up prediction formula. On these basis, the thesis develops gray systematic procedure GM.m with the aid of MATLAB, and proposes the combined-forecast method based on BP network ultimately, which regardsprediction results of exponential smoothing and gray system model as input datas of the network, and survey value as the output datas, the weighting of the input model is obtained through the network study, thus, the prediction model is established. Compared with the prediction errors of three kinds of prediction models mentioned above, this thesis analyzes the reason that each model produces error, and discusses the advantage and deficiency of each model in predicting groundwater water quality.The evaluation of the grade and section of current situation of groundwater pollution with artificial neural network theory and Nemerowint pollution index method is presented respectively. Based on these, the original causes, ways and Change law of underground water pollution in Shizuishan are analyzed, corresponding groundwater water quality protection and management measures are put forward.