In order to assess the water quality of Yuqiao reservoir, Benthic macroinvertebrates were sampled and collected from 10 sites in August 2014,among them 4 were considered as unimpaired or minimally impaired sites and 6 were impaired sites. Analysis was done for the 20 candidate biological index about its value distribution, Pearson correlation and judgment ability. Meanwhile,the total number of taxa, taxa numbers of aquatic insects and Crustacean+Mollusca,percentage of dominate taxa, the first three taxa and chironomid index were screened out to form a BIBI index system for Yuqiao reservoir. 4-point system and ratioing technique were used separately to obtain uniform dimensions of various parameters and BIBI value was the sum of the values of various component indices in the system. By using the each 20 percentiles of BIBI as a criteria to evaluate the aquatic ecosystem health,the results showed that,health criteria when BIBI>4.70,sub-health when 4.35~4.70,average when 3.54~4.35,inferior when 2.58~3.54,and poor when BIBI<2.58. The results showed that the total BIBI value of Yuqiao reservoir is 3.71,and the assigned score was 78.9, which belonged to the average level. Furthermore, we found that this method was imperfect to use BIBI as health evaluation standard of the sites without unimpaired or minimally impaired sites as reference sites,but it also had some reference for the general health evaluation of the reservoir by this method.%采用底栖动物完整性指数（BIBI)评价于桥水库健康状况，2014年8月根据于桥水库10个样点（4个参照点，6个受损点)采得的大型底栖动物数据，对20个生物指标进行分布范围、Pearson相关性和判别能力分析，确定构成于桥水库底栖动物完整性的指数为选取总分类单元，水生昆虫分类单元数，甲壳动物和软体动物分类单元数，优势分类单元的个体相对丰度，前三位优势分类单元的个体相对丰度，摇蚊个体相对丰度。用比值法统一量纲，计算各个生物指标的值，并将所得的值相加即得到BIBI指数值。根据BIBI指数值的25%分位数确定健康等级标准，并对小于25%分位数的值进行四等分，即得到于桥水库底栖动物完整性的评价标准。BIBI>4.70为健康，4.35~4.70为亚健康，3.54~4.35为一般，2.58~3.54为较差，<2.58为极差。结果表明，水库总体BIBI值为3.71，赋分值78.9，属于一般水平。结合对水库的综合生物污染指数评价比较发现，当参评水域缺少无干扰的参考点时，应用底栖动物完整性指标来评价该水域水质健康程度时还是存在一定的缺陷，但是对于水库总体健康水平的评估仍然具有一定的可参考性。
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