Research on Navigation-Obstruction Characteristics and Waterway Regulation Scheme of Multi-Branched River Reach in the Lower Yangtze River

Abstract

The Madang river reach in the lower Yangtze River is multi-branched and slightly curving. This paper combines measured data analysis with planar two-dimensional flow and sediment numerical modelling. Navigation-obstruction characteristics and waterway regulation measures were also researched and revealed the following problems : The south branch of the Madang reach is the main branch where the river regime is very stable. Navigation-obstruction characteristics primarily show that the right branch entrance at the Mianwai Sandbar may have a problem of insufficient water depth. The main flow of the right branch entrance of Guazihao Island (in the area of sunken ships) may result in navigation depth deteriorating. The transition section at the entrance of the Dongliu straight waterway is narrow and shallow. These problems can be solved by a series of remedial measures, including implementing beach protection projects at the head of the Mianwai Sandbar, a submerged dike in the left branch of Guazihao Island, a fish-bone type dividing dike at the head of Guazihao Island, a spur dike at the tail of Guazihao Island, and bank protection at key position. The aims of these measures are: aim to stabilize branches and create a better configuration of Guazihao Island for stabilizing the main flow of the right branch entrance of Guazihao Island and enhancing the transition shallow incision.