永定河流域水生态环境质量综合评价

永定河流域是京津冀区域重要水源涵养区和生态屏障。通过对流域30个站点的物理生境、水质理化、水生生物等指标进行评价参数选取、指标赋分及加权求和,获得永定河流域各站点水生态环境质量综合指数,基本可以代表永定河流域水生态环境质量状况。评价结果表明,永定河流域不存在清洁站点,除少数监测站点水生态状况为较清洁外,轻度污染和中度污染站点占据了永定河流域的大部分,可以看出永定河流域整体水生态状况不容乐观,这与该区域生态环境所受外部胁迫程度较强有关。对比了水生态环境质量综合指数与大型底栖动物完整性指数评价结果的吻合性,探讨了利用对永定河流域进行水生态系统状况综合评价的可行性和合理性,以期为河流管理和健康评价提供参考依据。

Comprehensive Evaluation of Aquatic Ecological Quality in the Yongding River Basin

Yongding River is an important water conservation area and acts as an ecological barrier in the Jing-Jin-Ji region. In this study, a comprehensive evaluation of aquatic ecological quality in the Yongding River basin was carried out, based on indices of physical habitat, water physicochemistry and aquatic organisms. The objectives were to provide data support and a reference for water environment management and aquatic ecosystem restoration in the Yongding River basin. Parameter measurements, index scoring and weight summing of the three indexing systems were determined based on monitoring of habitat, water physicochemical parameters and aquatic organisms at 30 stations in the tributaries and main stem of the Yongding River in April and September 2016. To calculate the comprehensive aquatic ecological index, the indices of physical habitat, water physicochemistry and aquatic organisms were assigned respective weights of 0.2, 0.4 and 0.4. The aquatic ecological quality of the Yongding River was divided into five grades: (1) clean, (2) relatively clean, (3) lightly polluted, (4) moderately polluted and (5) seriously polluted. Evaluation results for the basin indicated no clean stations, 23 stations were relatively clean or lightly polluted, 5 stations were moderately polluted and 2 stations were seriously polluted. The overall condition of the aquatic ecological quality was not satisfactory, a result of strong external stresses on the ecological environment. The results were consistent with those obtained using the benthic index of biotic integrity (B-IBI) and demonstrate that the aquatic ecological index is feasible and rational for evaluating aquatic ecological conditions in the Yongding River basin.