武夷山九曲溪水环境质量因子时空动态研究

Space-time Trends for Indexes of Water Quality from Jiuquxi Watershed in Wuyishan Scenery District

流域水体质量的演变是通过水环境因子的变化来体现，且随时间和空间发生复杂的变化．对2002-2007年九曲溪流域5个监测断面的6个重要化学指标DO、CODMn、BoD5、TP、pH及粪大肠菌群的空间变化、年变化及不同水期的变化特征进行对比分析．结果表明，几个化学指标的变化趋势基本一致，在空间上，上游水质优于下游、优于中游，中游水体污染相对严重；在时间上，2005年以前水质呈下降的趋势，2005年以后水质呈先上升后下降的趋势；在不同水期，枯水期水质劣于平水期和丰水期．整体上，九曲溪流域近6年来水质状况良好，水体呈中性偏弱酸性，D0含量丰富，还原性物质及TP含量不高，水体有较强的自净能力．污染源以沿岸集中排放的生活污水等产生的点污染源为主，其次为农业面污染源．研究成果以期为建立九曲溪水质模型提供必要的参数．

Space-time variation of water quality of a watershed changes with indexes of water quality. Six important indexes of water quality in Jiuquxi watershed are analyzed; and space-time distributions of these indexes are compared. The results show that different indexes have consistent tendency. In space, the water qualityof the upper reaches obviously is superior to that of the middle reaches and the lower reaches; the water quality of middle reaches is worse relatively and contaminated to different degrees. In time, the water quality became worse（2002--2005） ; subsequently became better（2005--2006） ; finally declined gradually after 2006. In different water seasons, the water quality of dry season was worse than that of the wet and normal season. Totally, the water quality of Jiuquxi watershed was better. Waters of this watershed are neutral and partial acidulous; concentration of DO is higher; contents of CODMn, BOD5 and TP are lower; so the waters have better self-purification capacities. The main pollutant source was the point source pollutants of sanitary sewage and domestic wastewater from Xingcun town; the next is agriculture non-point source pollution. The research results will provide the parameters to the water quality model for Jiuquxi watershed.