Abstract. According to the investigation of 25 stations in Hanjiang River Basin in August 2015 and January 2016, the aquatic health index of the region was evaluated by using the evaluation method. The diversity evaluation grade was light or non-polluting in August 2015 while diversity rating for the heavy pollution in January 2016. Water quality in the summer is better than that in winter season. The greater impact of plankton water quality factor for the total nitrogen and total phosphorus. water ecology evaluation results can better reflect Eutrophication and the degree of risk of algal blooms such as aquatic in water of Hanjiang River Basin.

Shifosi Reservoir is a plain reservoir. High groundwater level in the nearby area caused by impoundment of the reservoir has not only submerged the nearby farmland and village, but also reduced production and affected farmers' living. To analyze the influence of reservoir impoundment on surrounding groundwater level, Visual MODFLOW software was used to simulate the groundwater in Zhujiapu and Chenpingpu areas on the right auxiliary dam of Shifosi Reservoir. Results show that with the rise of the reservoir water level from 45.5 m to 46.2 m and 46.5 m, the area under the critical groundwater table (45 m) in the study area decreased in turn. In 2008, when the reservoir water level was 46.2 m and 46.5 m, the area under the critical groundwater level was reduced by 0.64 km 2 and 0.84 km 2 , respectively, compared with the case of reservoir water level of 45.5 m, and would decrease by 0.38 km 2 and 0.45 km 2 , respectively, by 2022. This indicates that the impact of reservoir impoundment on groundwater level is great. Therefore, relief wells or drainage ditches should be arranged along the auxiliary dam axis to effectively lower the groundwater level, and improve the surrounding ecological environment of the reservoir.

The investigation of benthic macroinvertebrates of Baiyangdian Lake was done in 2014. It contains the composition and diversity of benthic macroinvertebrates. Making an analysis of the survey result discovers that the diversity index of Yuanyang Island was the lowest as the sewage river entrance. No. 2 sampling point, which was the heavy polluted water, and the others were approximative, all being in the range of 1 ~ 2, which were the moderately polluted water. Therefore, we can say that Baiyangdian Lake was moderately polluted water. Richness, Shannon Wiener diversity index, evenness index of the three annual change trend was consistent, to analyze the correlation between the index of richness and Shannon Wiener diversity, the results shows that the correlation coefficient is 0.929, indicated correlation. The main groups of benthic macroinvertebrates freshwater lake in Baiyangdian Lake were including the mollusca, annelid and aquatic insects. Due to the sensitive of benthic macroinvertebrates to the change of environment, when the water was polluted, the benthic macroinvertebrates community structure and diversity will change, accordingly, the types and characteristics of community as an environmental evaluation index has been widely used in the monitoring of water quality in lakes.

The Zoobenthos in Baiyangdian Lake in Hebei province of China were investigated during August to October 2014, including the community structure and diversity. Total of 23 zoobenthic species were collected at 9 sampling sites, including 17 species of mollusca, 2 species of annelida and 4 species of aquatic insects, accounted for 73.91%, 8.70%, 17.39% respectively. The research would reflect the macrobenthos biomass in Baiyangdian Lake, then providing certain theoretical basis for ecological restoration in Baiyangdian Lake. Baiyangdian Lake is the largest wetland in the Haihe river plain, located in the central part of Hebei Province. It is famous for large areas of reed marshes and contiguous acres of lotus Lake, known as the Pearl of North China. Baiyangdian Lake plays an important role in maintaining the ecological system of wetland, regulating climate of Hebei plain and the Beijing Tianjin region, meliorating temperature and humidity conditions, increasing groundwater supply, maintaining the biodiversity and the source of rare species.

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