Abstract:

The Hongfeng Lake is the important resource of drinking water in Guiyang city. The water quality has been improving since 2007 under the centralized management, which achieved the anticipated goal basically. In this paper, we will pay more attention to the study of 10year variation trend of water quality from 2003 to 2012 and the monthly variation tendency in 2013 by monitoring the water quality of seven sections and four tributaries in the Hongfeng Lake. Meanwhile, we also analyze the reasons for such changes in water quality. The result shows that the water quality in the Hongfeng Lake worsen sharply from 2003 to 2007, from Ⅲ drop to bad Ⅴ. Then, the water quality changes up to the present Ⅲ, local Ⅱ after sixyear centralized management. However, influenced by intrinsic pollution and domestic pollution, it still existed excessive TP, NH3N, COD in part of the sections, so the water quality was in nutritional status in the whole. For another, water quality of lake changed obviously in different seasons. It appeared mild eutrophication in June and July affected by rainfall and temperature, but the rest of the month are in nutritional state. Besides, water quality of branches in the Hongfeng Lake was polluted to varying degrees, contamination level improved significantly till 2011, but four tributaries were still polluted by life pollution, mainly for excessive BOD5, fecal coliform bacteria and so on. According to these comparative experiments, the processing facilities need to be taken into account and the further management should be strengthened to deal with the pollutant source so as to achieve the requirements of water quality