Water environment improvements in Zhenjiang City, China

摘要

The Neijiang River is the main water body in Zhenjiang City, a medium-sized city in the east of China, located in the Yangtze River delta. With the long-term aim of improving water quality and restoring the aquatic ecosystem of Zhenjiang City, integrated physical and numerical modelling of the Neijiang River was carried out. A series of engineering measures was proposed based on modelling results. The first is the construction of a sluice and pumping station near the inlet of the main course of water passage, that is, the navigation channel. The second proposal is to build desilting basins on both sides of the sluice/pumping station. Results of physical experiments indicate that the sluice/pumping station can effectively regulate water exchange between the Neijiang and Yangtze Rivers and reduce seasonal water level fluctuations of the Neijiang River. Large quantities of sediment accumulate in the two desilting basins, resulting in obvious increases in river water transparency. Other measures proposed are a vegetated dam downstream of the second desilting basin and new ecotypic banks inside the Neijiang River and urban rivers. Newly planted vegetation on the vegetated dam and riverbanks has already greatly enhanced the self-purification capacity of the Neijiang River while naturally maintaining the city landscape.