河流生态修复是水环境与生态水利研究中的热点问题之一。其中，城市中小河流因流量小、污染严重且大多渠化而面临的生态系统结构和功能退化问题尤为突出。河流形态弯曲化正逐渐成为河流地貌修复的一种新方法，然而，弯道水流在复杂二次环流及横比降共同作用下的水沙运动、水质改善、河床演变规律和机理却不成熟。鉴于此，本研究从弯曲河道既可实现河流地貌修复，又存在可利用其复杂水动力条件来改善河流水质和底栖生物生境条件的思路出发，开展如下研究：（1）城市连续河湾现场的水力学条件、水质、底栖动物及生境调查；(2）弯曲河道内水流结构与河床形态演变规律；（3）弯道水流对水质的影响机制；（4）不同弯曲度对底栖动物生境质量的改善机制。最终，揭示出河道不同弯曲度对改善城市中小河流的水质和水生生物生境条件的机理，并建立河道弯曲度对河流生态环境影响的评价体系，为改善城市中小河流的生态环境提供理论和技术支撑。

River ecological restoration is one of hotspot issues in the research field of water environment and ecological water conservancy. Due to low flow, water pollution and channelization of small-medium city rivers, the health and ecological degradation problems of these rivers become much more prominent. Meandering of river shapes is a new restoration method of river topography and geomorphology. However, the water and sand movements, water quality improvement and river bed evolution with the actions of secondary flow and transverse surface slope in meandering flows are not yet fully known. Considering the meandering of river channel can not only restore the topographic features, but also improve the water quality and benthos habitat diversity in a river, in this research project, we plan to conduct following studies: (1) field investigation at river reaches with continuous meandering of a city river about its hydraulic conditions, water quality, macrozoobenthos and its habitat; (2) flow structure and river bed evolution in the meandering rivers; (3) influences of meandering flow on water quality and (4) the effectiveness of meandering degrees on the habitat quality of the macrozoobenthos. Through comprehensive analyses, we will reveal the mechanism of improving the water quality and habitat quality of zoobenthos in small-medium city rivers by different meandering degrees, and furthermore establish an assessment methodological system for improving water environment and ecology, which can provide theoretical and technical supports for improving water environment and water ecology of small-medium city rivers.