红枫湖水质变化趋势及原因分析

VARIATION TREND OF WATER QUALITY AND ITS CAUSING EFFECT OF THE HONGFENG LAKE

红枫湖是贵阳市重要的饮用水源地,自2007年集中治理以来,水质不断好转,基本达到预期目标。对红枫湖流域7个断面及4条入湖支流水质进行监测,研究2003~2012年10年的水质变化趋势和2013年年内变化趋势,并对引发水质变化的原因进行分析。结果表明,从2003年到2007年红枫湖水质急剧恶化,从Ⅲ类降到劣Ⅴ类;经过6年的集中治理,水质提升至目前的Ⅲ类、局部Ⅱ类,整体处于中营养状态,但受内源污染和外源生活污染等影响,部分断面仍存在TP、NH3-N、COD等超标现象。湖库水质季节性变化明显,受降雨及气温影响,在6月和7月出现轻度富营养化,其余月份均处于中营养状态。红枫湖4条入湖支流水质受到不同程度的污染,2011年后水质状况好转,但支流水体呈现受生活污染源污染的显著特征,主要表现为BOD5、粪大肠菌群超标。因此,对影响水质的污染源还需要增加处理设施,加强管理,以达到水源地水质的要求。

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 2012and 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 badⅤ.Then,the water quality changes up to the presentⅢ,localⅡ after six-year centralized management.However,influenced by intrinsic pollution and domestic pollution,it still existed excessive TP,NH3-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 BOD5,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.