Study On Southern Jiangsu Towns’ Water Quality Comprehensive Assessment Method

Most Southern Jiangsu town is small and densely populated area. River interlace each other, some ancient towns built next to the river. In recent years, due to the urbanization process accelerate, the higher industrialization level of southern Jiangsu town is, The more serious breaking brought by human production and life to closed water is. Water environment remediation and renovation has been attracted great attention and concern of government and society.The evaluation of water environment quality is a basic work of starting to prevent and control water pollution. There are thousands of water quality assessment methods, so far, it has no unified standard and norm at home and abroad. Water environment management department unfolded water quality assessment at will; the single-factor assessment is recommended by current Environmental quality standards for surface water(GB 3838— 2002) has the limited effect. Therefor, in order to assess southern Jiangsu towns’water quality more scientific and rational, the study was carried out through compared and improved varieties of evaluation methods, ultimately found the most applicable one on southern Jiangsu towns’water.Tongli Town—a typical Southern Jiangsu town, was established as the sudy area, to the results of 20 monitoring sections from March 2012 to February 2013 as original data. By SPSS R-type and Q-type cluster analysis, proposed monitoring optimized plan. Former 20 monitoring sections were reduced to 8, monitoring indicators could be divided into 8 categories. CODCr、TN、DO、Transparency these four key indicators were analyzed of espatial and temporal variation.Among lots of methods, focus on researched comprehensive pollution index、principal component analysis、correspondence analysis、fuzzy synthetic assessment. Six membership functions、entropy weight、the effective degree of maximum membership degree principle、 and confidence criteria were combined into improved fuzzy synethetic assessment. compared to the original way, the improved process was able to estimate inferior V water quality, weight calculation was simple even can determine the main pollution factor, the results of assessment was more reasonable and reliable, meanwhile, distinguished the different degrees more accurately.Use above methods, water quality assessment of Tongli Town was conducted. Through comparison and analysis of results, concluded as follows:combination and application of improved fuzzy synthetic assessment and correspondence analysis method is worthy to spread in Southern Jiangsu towns’water quality comprehensive assessment.The evaluation results showed that, there were 7 sections reached Grade inferior Ⅴ, 8 sections reached Grade V,5 sections reached Grade Ⅳ, water qualification rate was only 25%; Longhai Bath Center and Dongchuan Bridge were suffered the most serious polloution, lightest pollution were Jinkou Pumping Station, Wo Yunan Bridge, etc. External water of scenic was better than internal one, the region of residents dispersed was better than people concentrated area. Domestic and tourism pollution were main sources in Tongli Town was verified. The main pollutants were nitrogen and phosphorus nutrients, primary pollution factor was TP, water quality presented eutrophication, organic pollution degree was general, water scenic sensory function was affected by more suspended solids in the water.