CHARACTERISTICS AND CAUSE OF LAKE EUTROPHICATION IN JIANGSU PROVINCE WITH SUGGESTIONS ON ITS CONTROL MEASURES

On the basis of the trophic evaluation criterion of lakes,the eutrophication status of most lakes in Jiangsu Province were estimated,with the analysis on the cause of formation and controlling ways in south area and north area in Jiangsu, as well as in outskirts of cities. It is indicated that all outskirt lakes were eutrophic or hyper-eutrophic; the lakes in north Jiangsu were meso-eutrophic, and similar to the lakes in south Jiangsu. The trophic degree of lakes in east Lake Taihu was one grade higher than those in the west. The majority of lakes in the north in Jiangsu are water-carrying, liable to suffer from industrial and agricultural waste water in pulse discharge. The cause of lake eutrophication in south Jiangsu is more complex and they were mainly impacted by town effluent and industrial and agricultural waste water which hold nitrogen and phosphorus in high concentration. The efficient ways to control eutrophic lakes in Jiangsu Province is to strictly controlling headstream discharge of the pollutants from the various pollution sources in catchments, adequate application in wetland purification function of the net-rivers and to perform some environmental engineering of sludge dredging and ecological reconstruction in moderation.