Abstract:

Eutrophication has been identified as the leading cause of impairment to Dianshan Lake.To address the issue of nutrient enrichment,government has established many nutrient management plans.It appears hard to approach exist water quality standards due to no criteria set for eutrophication.In this paper,based on 25 years nutrient data,we discussed the statistical method to set quality criteria for total P (TP) and total N (TN) and compared them with existing Taihu criteria.We calculated potential nutrient criteria by time series analysis and frequency distribution methods. The recommended criteria value of TP was 0080 mg/L. The contents of TN were higher in the cold season than in the warm season.We divided TN in winterspring and summerautumn periods for analysis.The recommended criteria value of TN in winterspring time and summerautumn time were 077 mg/L and 213 mg/L,respectively