Study On The Groundwater Environmental Quality Assessment Methods

Water is the most widely distributed on the earth. It is not only a matter of natural resources,but also an important strategic resources. It is lifeline of human survival and the development of social production,to realize the sustainable development of the foundation and the core of environmental problems and development issues. The groundwater resource is an important part of water resources system. Therefore, there is an important significance for taking effective measures to protect the groundwater, strictly controling and preventing of groundwater pollution, satisfying human survival and development, the production and the life.The groundwater environmental quality evaluation is that water pollution and protective measures, this is a fundamental, fist work. Is the rational development and utilization of groundwater resources and protection of groundwater environment, one of the important tasks.The groundwater environmental quality evaluation is evaluation of groundwater quality condition and timely finding water pollution and protective measures. This is a fundamental,prospective work;premise of rational development and utilization of groundwater resources and also one of the important tasks of protection groundwater environment.Our country groundwater environmental quality assessment work is the latter and need further perfecting the quality evaluation method.Therefore, it is necessary to a set of accurate and simple, practical and effective groundwater environmental quality assessment methods. The set method can qualitatively and quantitatively analyze groundwater environmental quality situation and future trends of development and provide powerful foundation for groundwater resource planning, management and governance pollution. To set up groundwater pollution, water security warning system. It is beneficial to set up warning system of groundwater quality and pollution and ensure harmony of people and water.The paper mainly studies and research results are as follows:Based on the dialectical analysis of the traditional Nemero synthesizing pollution index method,from the water environmental quality assessment of weight and extreme two important factors,this paper makes the improvement of the traditional Nemero synthesizing pollution index method,determine the optimal allocation of weight, weight method, find out the maximum and times larger values by a standard for principle of bigger harmfulness and more strict request of pollution factor,the smaller standard limits and greater weight.Designate some kind of water body standard from the national newest promulgation water environment quality standard (GB/T14848-93) and choose pollution factor which is same with the testing water body sample, and designate that the water body is a datum, calculate the Nemero integrated pollution index of other kind of standard water body to realize the sole pollution degree digit indexing. The Nemero integrated pollution index of the selected benchmark water bodies is1. Similarly, calculate Nemero integrated pollution index of the testing water basing on the selected standard benchmarks and evaluate the water quality under test.The partition pollution levels and evaluation method have identity, flexibility and the body without the number of restrictions of pollution factor to develop standards which can be divided into what kind of grades.From the new improved formula of improvement and determined to pollute gradation and realize evaluation,we more scientifically and reasonable construct a comprehensive Nemero pollution index for groundwater environmental quality assessment of complete system. The model is applied to PanShiShi groundwater environmental quality and is more objective than traditional method.In recent years, neural network in the field of water environmental quality assessment, there are many applications,but also exists some problems, such as the study sample learning for a long time,no selectivity and fitting etc. We proposed Hierarchical clustering—Neural network coupling model by organic combination of Hierarchical clustering and Neural network,and use a new network evaluation standard to Determine the appropriate system accuracy. The model is applied to PanShiShi groundwater environmental quality and is more objective than traditional Neural network.In neural network, the most fundamental and most key problem is the study of the sample. We change the establishment model of traditional learning samples on water environmental quality assessment and augment learning sample number in some relative error range expansion to guarantee the learning samples representative, tolerance, and lay the foundation for the correct evaluation, also to the neural network in other fields of application provides a method to create learning samples, enlightenment and reference. We perfect through neural network from three aspects of amplification learning samples and coupling of system clustering method and neural network and introducing "approximation degree" this concept in the network evaluation and evaluate PanShiShi groundwater environmental quality with this method.The evaluation results of various methods are compared and analyzed, Advantages and disadvantages are pointed out;The conclusion and suggestion are given.In order to adapt to the need of human health life, to the harmony of human and nature, to the sustainable development of social economy, should accelerate standards for water environment quality and revision. Standard is the foundation and fundamental evaluation standard. We cannot evaluate without standard.The weight of the reasonable or not is the key to whether the evaluation results objectively. Determine the pollution factor weights of evaluation of groundwater environmental quality is an important research content. Many methods of determining weight related experts in the field, the method of counterpoising truly cannot be ignored.We should consider between pollution factors, the relationship between the correlation with a reflected in evaluation results.We strengthen scientific research, joint toxicity in water pollution factor for the level limit.Along with the development of science and technology, and the groundwater environmental quality assessment methods in the gradually study and the relevant new evaluation methods will continue to get development and utilization. The evaluation result will play more and more objective reality. The groundwater environmental quality assessment will develop into space by the time, from the static and dynamic development to the evaluation of development by timing to instantaneous evaluation. Thus all the groundwater environmental quality monitoring, provide data of the change. The groundwater environmental quality analysis laies a good foundation for the change trend of water environmental health, forecasting and warning.