杭州地区大中型水库富营养化状况及影响因子分析

在2008年和2009年对杭州地区17个大中型水库进行了调查。结果表明：杭州地区大中型水库水质不容乐观，按照单因子指标评价法，只有3个水库符合Ⅱ类水体标准，2个水库符合Ⅲ类水体标准，2个水库为Ⅳ类水体，3个水库为Ⅴ类水体，其余7个水库均为劣Ⅴ类水体，定类指标均是总氮。根据综合营养状态指数结果：丰水期2个水库处于贫营养状态，13个水库处于中营养状态，2个水库处于轻度富营养状态；枯水期16个水库处于中营养状态，1个水库处于中度富营养状态。总氮和总磷作为营养物质是这些水库富营养化的主要影响因素。位于山区源头地区的水库水质最好，位于平原城乡附近的水库其次，位于城市下游及城区附近的水库水质最差

EUTROPHIC STATES AND INFLUENCE FACTORS OF LARGE AND MEDIUM SCALED RESERVOIR IN HANGZHOU AREA

In order to understand the water environment of reservoirs, an investigation was conducted on the water quality in 17 large and medium scale reservoirs of Hangzhou City, China. The results showed that the water quality of those reservoirs were not optimistic. According to a single factor index, the water qualities of three reservoirs met Grade Ⅱ water standards, two reservoirs met Grade Ⅲ, two reservoirs met Grade Ⅳ, three reservoirs met Grade Ⅴ and seven reservoirs were worse than Grade Ⅴ. The specific index determining the classes was total nitrogen in all cases. According to trophic state index, in the wet season two reservoirs were oligotrophic, thirteen reservoirs were in mesotrophication and two reservoirs were light eutrophication; in the dry season sixteen reservoirs were in mesotrophication and one reservoirs was in moderate eutrophication. Total nitrogen and total phosphorus were the main factors affecting eutrophication. The results of cluster analysis showed that the seventeen reservoirs were divided into three categories. Qinshan and Fuchunjiang reservoirs were identified as a class for the bad water quality; Tongshan, Xiayuan, Fengshuling and Yanjia reservoirs located in the upstream region of Xinan River and Xinanjiang reservoir were identified as the second class for the good water quality; the remaining ten reservoirs were identified as the third class. The reservoirs located in mountainous region had the best water quality, reservoirs near the town followed and reservoirs located near the city and downstream city had bad water quality. Different regions and different types of reservoirs had different pollution reasons. For different reasons we should implement corresponding countermeasures to prevent and control reservoir pollution