Arc-GIS软件在太湖水质及富营养化分析中的应用

Application of Arc-GIS to analysis of water quality and eutrophication of Tai Lake

目的了解太湖水质及富营养化情况，特别是氮磷营养盐及富营养化状况空间分布特点。方法于2011年对太湖20个点位水质及富营养化指标[水温（wT）、pH值、溶解氧（DO）、叶绿素a（Chla）、透明度（SD）、高锰酸盐指数（cOD。）、总氮（TN）、总磷（TP）等1进行监测，应用Arc—GIS软件绘制太湖水质与富营养化指数（Tu）分布图。结果太湖TN浓度范围为1．39—5．26mg／L，TP浓度范围为0．04—0．19mg／L，COD№浓度范围为3．2—6．0mg／L，Chla浓度范围为0．013～0．039mg／L，TLI范围在51．7—66．7。GIS绘图显示各项水质指标浓度及富营养化指数均呈现出”西部高、东部低”的分布规律，高低浓度差异较大。结论本次监测的太湖水域存在富营养化现象，太湖西北部的竺山湖及附近沿岸水域为污染最严重区域。

Objective To study the water quality and eutrophication situation of Tai Lake, especially the spatial distribu- tion characteristics of nitrogen, phosphorus and trophic level index （TLI）. Methods The water quality and eutrophication in- dices such as WT, pH, DO, Chl a, SD, COD, TN, TP and so on were monitored at 20 monitoring sites of Tai Lake in 2011, and Arc-GIS was used to draw TN, TP, COD~, Chl a and TLI concentration distribution maps. Results TN concentrations were between 1.39 and 5.26 mg/L, TP were between 0.042 and 0.188 mg/L, CODM, were between 3.2 and 6.0 mg/L, and Chl a were between 0.013 and 0.039 mg/L, TLI were from 51.7 to 66.7. The distribution maps were all showed a spatial distribution law that water quality indicator＇s concentration and TLI of Tai Lake were ＂west high and east low＂. The concentrations of west side were much higher than the east side＇s. Conclusion The northwest side, especially the Zhushan Lake, is the most severely polluted area of Tai Lake.