Regulation Method of Shoal Waterway of Seasonal Navigation in Dongting Lake ——illustrated by the regulation of Qixingdui Shoal between Anxiang and Maocaojie

The waterway from Anxiang to Maocaojie lies on the lower reaches of Songzi River and Hudu River after their confluence in flood diversion area of Yangtze River. This waterway is a seasonal stream. Its conditions of water,sand and evolution is different from those of plain river shoal. Erosion plays main role in the shallow main stream when sand is carried smoothly during flooding.It leaves mud in the shallow when the water of the rivers or the water level of Dongting Lake rises. In this paper,a typical example of Qixingdui shoal is shown. It sums up the thoughts of design and the principles and methods of regulation for this kind of dangerous shoals. A survey is made on this kind of shoals to find the design principle of grooving arrangements and regulation.