Three Gorges Five-Stage Ship Lock

Three Gorges Five-Stage Ship Lock - Brief Introduction

The major navigable channel of Three Gorges is the two-way five-stage ship lock. It is 1621 meters long with a total head drop of 113 meters from the upstream to the downstream. Its annual tonnage capacity is 50,000,000 tons, the largest in the world. There are five lock chambers, each of which is 34 meters wide and 280 meters long. The head drop between each two steps ranges from 22 meters to 23 meters. Every time, three 3000-tonnage barges and a ten-thousand-tonnage fleet can pass it.

Because it is a two-way ship lock, the uplink and downlink are respectively proceeded. To the north bank is the north-line lock and it conducts the uplink work while beside it is the south-line lock which conducts the downlink work. All the vessels ought to report to the lock dispatching office 24 hours earlier. Passing the five-stage ship lock in Three Gorges Dam, the tourists can enjoy the grand view of "smooth lake coming from steep gorges".

Three Gorges Five-Stage Ship Lock - Characters of its Gate

The gate at each lock consists of two doors. Each door weighs 800 tons and is 20.2 meters wide and 39.5 meters long with about the same area of a basketball court. It is the rare huge gate in the world. After closing the doors, people can find that the gate is not flat. Instead, it is like the shape of Chinese character "ren " (person). This is to press the gate tight with the help of high water pressure, thus strengthen the leak tightness.

Three Gorges Five-Stage Ship Lock - Operating Principle

Since the head drop (113 meters) is too large, the ship lock is composed of five stages. The operating principle of the five-stage ship lock is the same as that of communicating vessels. Its conveyyance system is connected to the water. So the water can be injected to the lock chamber and then the water level in side the lock chamber can be flush with the water level in the reservoir. Its discharging system is connected to the downstream water. So the water in the lock chamber can be discharged to the downstream and then the water level of the lock chamber can be the same with that of the downstream. Vessels can rise and fall gradually with the water rise and fall in the lock chamber.