Eevolution Tendency of Water Quality and Eutrophication Analysis of an Artificial Lake— Dishui Lake

Main water quality indicators of Dishui Lake in Shanghai were monitored for six consecutive years. The results showed that the salinity of the lake decreased from 3 to 1 since the impound in 2004; the N/P also showed a declining trend year by year and phosphorus was the limiting nutrient element in Dishui Lake; the water quality in the lake remained at the level of Ⅳ to Ⅴ class of surface water; the major pollutants affecting water quality were CODMn, TP, TN and BOD. The analysis of monitoring data indicated that the variation trend of eutrophication was generally consistent with that of chlorophyll a content in the lake, and TP was the main indicators impacting the chlorophyll a content and the eutrophication of the lake. In addition, eutrophication index was prone to rising in summer and autumn.