The Study Of The Methods To Comprehensively Appraise Groundwater Quantity

Water is an absolutely necessary resource to Man. In our country, there are a lot of people, but water resource is inadequate and water distributing is quite imbalance. Groundwater is an important composing of water resource, with many advantages such as high quality, abroad distribution and convenient to exploit. It is counted that 70 percent of population in our country mainly give priority to groundwater. In the north, groundwater is used frequently. For example, the proportion of groundwater used in the river-sea valley reaches more than 90%, and groundwater account for more than 50% in all using water quantity. Groundwater plays an important role in people's life and yielding, in the meantime it is also a restrict factor on our country's continuable development.When people exploit groundwater, the environment of groundwater is changed. As a result, the problem on water quality pollution is arising. Owing to long recurrence and weak cleaning-self power, groundwater is easily polluted and resumed difficultly, resulting from improper exploitation. This will do damage to environment and do harm to Mankind as well. In addition, it is difficult to discover groundwater pollution. Therefore, to the prevention and cure of groundwater pollution, we must prevention firstly. We should supervise groundwater resource and appraise groundwater quality properly, which is a premise on proper exploitation of groundwater resource, and an important task to protect the environment of groundwater.In the former four charts, this paper respectively introduces the theory and process of comprehensive index method, fuzzy complex index method, grey clustering method and BP nerve network method from science, comprehensive, accurate and practical angle. Then these methods are applied in the dive water quality estimate of Yinchuan region. In chapter 5, combined with actual hydrology geology condition, appraising result to four kinds of methods are contrastively analyzed, it puts great emphasis on analyzing their applicability, advantages and disadvantages.Through the research, it can show: four kinds of appraisement methods all belong to the Comprehensive evaluation model, their conclusions of the water quantity evaluate also are basic consistent. They deduce careful, have the sufficient theories basis and the rationality in the appraisement, and can be applicable to the water environment appraisement. Although the every kind of evaluation method has its characteristics, every kind of evaluation method all contain its limitations from the mathematics principle, and all need to be examined continuously, improvement with gradually perfect.