EFFECTS OF ARTIFICIAL CUTOFFS IN MIDDLE YANGTZE REACH

摘要

The artificial Cutoffs of Zhongzhouzi and Shangchengwan river bends of lower Jingjiang in middle Yangtze reach were completed more than 35 years ago. New river channels have developed as anticipated and old river bend channels are being silted up. The amount of sediment deposition in old channels is larger than the amount of erosion in the same period in new channels. The river channel slope upstream from Cutoff is increasing with riverbed erosion and the water stages for the same flow discharges drop lower. The stretch downstream from Cutoffs to Chenglingji experiences no sedimentation and appears slightly eroded, and there is no rise of water stages for the same flow discharges. Revetment and bank protection works are carried on successively for the new river channel. The present fluvial regime of lower Jingjiang is steady as a whole, and the artificial Cutoffs are bringing forth their long-term positive effects.