Analysis On Space-Time Variation And Influencing Factors Of Water Quality Of Drinking Water Sources In Rural Areas Based On GIS

In the process of rural economy of our country, many towns and villages’drinking water sources have been destroyed because of artificial negligence, there is a decline of water yield and water quality, drinking water safety is threatened. The towns and villages’drinking water safety is mainly affected by the source water quality, water treatment process and water distribution system. Because of the late start, lack of money and other reasons, protection of drinking water source in these areas is less developed, strengthening the protection of source water quality is become more and more important. In order to protect water quality of drinking water sources, first, real-time, accurate grasp of the dynamics of water quality, and reasonable water quality evaluation are necessary, which are not only the important contents of rational planning, management and protection of drinking water resources, but also the keys to ensure the safety of drinking water in villages and towns.This paper bases on the situation of Chinese villages and towns’ drinking water sources, constructs a drinking water safety evaluation system for these areas, also selects typical drinking water sources, investigates water quality data, combines with GIS technology, a geographic information system is established to draw a graphical visualization map of spatial and temporal distribution of water quality. Through comparison and analysis of different water quality assessment methods, the Method of Single Factor Index and the Method of Comprehensive Evaluation Index are selected to evaluate the water quality’s temporal and spatial variation, water quality distribution patterns are studied and pollutions in key areas are recognized. The SPSS19.0is used to analize status of water quality, key factors’concentration and influencing factors by Pearson, the mainly influencing factors on water quality are identified.Through evaluation analysis, the main conclusions of this paper are following:(1)Using the Single Factor Index Method, the Method of Comprehensive Evaluation Index and the the Method of Fuzzy Comprehensive Evaluation to compare and evaluate, the results show that:the Method of Single Factor Index, which turns out to be relatively conservative than comprehensive evaluation on water quality, mainly highlights the most serious pollution factors on water quality; Both the Method of Comprehensive Evaluation Index and the the Method of Fuzzy Comprehensive Evaluation consider the influence of various water quality factor, evaluation results are more close to the water quality objective conditions compared to that the Method of Single Factor Index. However the Method of Comprehensive Evaluation Index compared to the Method of Fuzzy Comprehensive Evaluation is easier to operate, more suitable for water quality evaluation of villages and towns’drinking water sources. (2)Using the Method of Single Factor Index and the Method of Comprehensive Evaluation Index to evaluate the space-time changes (form2010to2012) of water quality of130typical drinking water sources in China, results show that:the river type source has a trend of improvement in the water quality, while the lake reservoir type source has a deterioration tendency; the water quality of river type source has clear boundaries between seasons, which is best in summer, good in autumn and winter, worst in spring. While the water quality of lake reservoir type source’s seasonal variation is not obvious. Through evaluation and analysis, the main water pollution factor was NH3-N, CODMn; the spatial distribution of water quality has a certain difference, water quality is relatively poorer in the densely populated and industrialized regions.(3)Correlation analysis on water quality, key indicator concentration and influencing factors shows that:villages and towns’drinking water quality is not seriously affected by precipitation; in terms of social factors, the low population density, the little influence on water quality, while the development of rural economy affects more obviously on water quality. Waste water form Villages and towns’ enterprises and agriculture are the main pollution source; in the aspect of land use types, the proportion of cultivated land area and woodland is significantly correlated with the water quality, land use types have a certain effect on water quality of villages and towns’drinking water sources.The water quality evaluation system and application of GIS can be used to assist researches which study water quality of drinking water source and its space-time changes in rural areas. The research findings will provide support to recgnize the status of water quality of drinking water sources and its influencing factors in rural areas in China.