Spatial Variability Of Water Quality Parameters In Rivers

Suzhou, a leading edge city with economics'swift growth, water environment protection in this region is taken into account. The water quality within this city increasingly goes to bad due to the rapid advancement of its industrialization and urbanization. It has become a key restrict to the continuous development of Suzhou. Therefore, it′s necessary to analyze and study the spatial variability of water quality of rivers in the region, which directly shows the geographical variability of pollution in the rivers, and this work has a positive guidance to the evaluation and planning of rivers in Suzhou.In this article, we monitored three main parameters COD_Mn,NH₃-N,TP of water quality in the rivers, which within 320km² of Suzhou city. It first evaluates the water quality by using the method of Fuzzy Comprehensive Evaluation; then analyzes the temporal and spatial variation features and variation trends of different water quality parameters of rivers by methods and theories in Geostatistics. The main study process and conclusions are digested as below:(1) It analyzes the current status of the region's three water environment pollutions with the monitoring data of chief rivers in three water seasons in year 2009 and 2010. The results shows that among the three water seasons they have better controls to the COD_Mn pollutions, and that the major factors come from the pollutions by NH₃-N and TP. Particularly, the monitoring sections the former has exceeded V Grade of surface water on average.(2) It comprehensively evaluates and analyzes the water quality in three water seasons of the major rivers by the method of Fuzzy Comprehensive Evaluation. The results show that the water has been polluted in various degrees. Take dry season as an example, stream courses were polluted completely, exclusive of sections X1 and 46, the comprehensive water quality of other sections were worse than V Grade.(3) It compares the spatial interpolation of organic empoison comprehensive indexes and eutrophic indexes and draws a contour map of Space-time distribution characteristics, to reveal the temporal and spatial variation features and variation trends of different water quality parameters of the region's rivers, by the methods of the spherical model variogram and Kriging. The results show that the rivers water quanlity index assumes space-temporal aberrance characteristics, and is affected by factors such as different sources from areas, differences of rivers courses, differences of water seasons, aquatic plants, even water flows, etc; and that water quality of various indexes were seriously polluted, especially, the content of Nitrogen and Phosphorus of the eutrophic indexes is remarkable.(4) From the sources of river pollution to view, the rivers of Suzhou city has seriously affected by indigenous pollution, which mainly include three parts of sewage from industry and town living, and urban surface runoff.