Dams, weirs, and flood-gates are composed of a fixed part and a movable part. The former includes a weir column. The latter contains a leaf and its moving system.
Almost all the dimensions of a leaf are decided by the cross-section of the channel and the river width. The movable part of a leaf is usually called a gate-valve system and has been improved with the development of machius and their control technology.
In this paper, the authors analyze the history of the gate-valve system. This analysis gives us the precious suggestion on the improvement of new types of gate-valve system.
