THREE GORGES DAM Three Gorges Dam is a

THREE GORGES DAM

Three Gorges Dam is a hydroelectric dam on Yangtze River in China. The river is the third longest river in the world.

Five other dams were built before for the construction of the Three Gorges Dam. These dams are; -Debdon Dam (4 k. W) -Mareges Dam (128 MW) -Hoover Dam (1. 345 MW) -Grand Coulee Dam(2. 000 MW) -Krasnoyarsk Dam (6. 000 MW)

Three Gorges Dam is a concrete gravity dam with 2. 3 km long and 181 m high above the rock basis. The maximum chamber volume is 39 cubic kilometres.

Dam construction began in 1993 and was completed in 17 years. Total cost is USD 27 billion. 40. 000 people worked in this project as construction worker.

The power generation capacity of the dam is 22. 000 megawatts. The dam is the biggest hydroelectric power plant in the world.

PURPOSES OF THE THREE GORGES DAM Generation of electricity Flood Control River Transportation

Development and construction of the Three Gorges Dam was carried out by "China Three Gorges Project Corporation“.

Made of concrete and steel, the dam is 2. 335 m long and the top of the dam is 185 metres above sea level. The project used 27. 2 million cubic metres of concrete, 463. 000 tonnes of steel and moved about 102. 6 million cubic metres of earth.

CONSTRUCTION STAGES

During the construction of The Three Gorges Dam, converting of the river was provided with a very interesting approach. Rotation system was implemented gradually with the help of cofferdams, benefiting from the Zhongbao island at the dam site.

First stage of the construction: 1993 -1997; Inter of the island the right side of the beach were closed with cofferdams. A space was arranged for the passage of vessels. The passage of the vessels were provided from the left side of the beach during this time.

Second stage of the construction: 1998 -2003; The dam and the power plant were constructed which on the left side of the beach. Sluiceways and spillways were consructed on the middle. The passage of the vessels were provided from the right side.

Third stage of the construction: 2004 -and than; The construction of the right side was completed.

(a)Natural State (b) First stage of the construction (c) Second stage of the construction (d) Third stage of the construction

SPILLWAY AND SLUICEWAY

Sluiceway : An artificial channel, especially one for carrying off excess water.

Spillway: An incision on the crest of a transverse structure through which water flows.

23 pieces of sluiceway are located on the central part of the Three Gorges Dam which is crest long 483 m. Sluiceways have sputtering tipped.

The spillway has 22 opening. Spillway sprays water into the air to break up energy.

The dam’s spillway capacity is 102. 500 m 3/s, about %40 of it from the spillway, %40 of it from sluiceway, %20 of it passes through the turbines.

POWER PLANTS

The Three Gorges Dam is the world's largest capacity hydroelectric power station with 34 generators: 32 main generators, each with a capacity of 700 MW, and two plant power generators, each with capacity of 50 MW, making a total capacity of 22, 500 MW.

Among those 32 main generators, 14 are installed in the north side of the dam, 12 in the south side, and the remaining six in the underground power plant in the mountain south of the dam.

Photo shows the interior scene of the Three Gorges underground power station.

SHIP LOCKS AND SHIP LIFT

The locks are 280 m long, 35 m wide, and 5 m deep.

The installation of ship locks is intended to increase river shipping from ten million to 100 million tonnes annually, as a result transportation costs will be cut between 30 and 37%.

These ship locks are the biggest in the world.

SHIP LIFT In addition to the canal locks, a ship lift, a kind of elevator for vessels, was constructed. The ship lift is designed to be capable of lifting ships of up to 3, 000 tons. Ship lift is the biggest in the world.

POSITIVE AND NEGATIVE EFFECTS OF THE DAM

As well as producing electricity, the dam is intended to increase the Yangtze River's shipping capacity and reduce the potential for floods downstream by providing flood storage space.

The Chinese government regards the project as a historic engineering, social and economic success, with the design of state of the art large turbines and a move toward limiting greenhouse gas emissions.

However, the dam flooded archaeological and cultural sites and displaced some 1. 3 million people, and is causing significant ecological changes, including an increased risk of landslides.

The dam has been a controversial topic both domestically and abroad.