Analysis on Eutrophication of Dianchi Lake and its Control Measures

The monitoring data of the Dianchi Lake during 1988-1999 shows that the water quality has been deteriorating and exceeded Grade V and the trophic level has been constantly rising.In the part of the Waihai,the TP concentration doubled,Chla concentration rose by ten times,and the trophic level went up from eutrophication to hyper-eutrophication over the past ten years.The increase of P concentration is the principle reason for the aggravation of the eutrophication.Nutriments of the Dianchi Lake mainly come from domestic wastewater and the agricultural source.The nonpoint pollution is the primary causte of the deterioration of water quality in the Waihai.The treatment of the Dianchi Lake focused on point pollution and the control of pollution source within the Caohai and no non-point control and lake ecological treatment have been conducted.In this case,this article makes a special emphasis on the strengthened treatment of non-point pollution,lake ecological rehabilitation and management.