水流-泥沙协同运动对受损河流物理生境的修复作用

Using eco-engineering methods, the rehabilitation effects of flow-bedload co-movement on physical habitat of a damaged river were investigated; the quantitative response relationship between ecological process and hydraulic dynamic was analyzed. The results show that (1) 4 alternative physical habitats (sandbars) are observed in the experimental river reach, which is due to the drive of flow-bedload co-movement. Under the influence of 4 typical floods, the area and position of the sandbars are in a dynamic change. (2) In the changing process of river physical habitats, the composition of sandbar matrix changed. (3) According to the suitability index of river physical habitat matrix, the quality of physical habitat matrix in the experimental site has not been improved remarkably in the primary rehabilitation period. But after 1 year's rehabilitation, the quality of physical habitat matrix in the experimental site has been much better than that in the control site. (4) The species and diversity of benthic macro-invertebrate in the experimental site increase greatly compared with those in the control site. 8 and 3 benthic macro-invertebrate species are found in the experimental site and in the control site, respectively. (5) Medium and small floods play a very important rehabilitation role in the formation, change, and quality promotion of river physical habitat. When a large flood happens, some sandbars may disappear. But the disappeared sandbars will be regenerated and rehabilitated through the flow-bedload co-movement, if the curvy characteristic of the river has not been destroyed. Ecological and hydraulic theories are enriched and developed by this work, and scientific evidence is provided for river ecological rehabilitation.