Data from the QQ website said that before the Three Gorges Dam was built, a large flood occurred every 10 years in the central and downstream of the Yangtze.

In 1954, for example, a major flood in the upstream caused many dams and embankments downstream, causing more than 3.18 million m2 of agricultural land, causing the Beijing-Guangzhou railway to stop. operated for more than 100 days and affected nearly 19 million people.

This flood caused the downstream provinces to take damage for many years.

So the Chinese Government later approved the construction of the Three Gorges to prevent floods that year from having a chance to recur. According to QQ, since the Three Gorges Dam was completed, the phenomenon of widespread floods and rains in the downstream will no longer occur.

Many people ask, if the Three Gorges Dam has such good flood resistance, why not China build some similar irrigation facilities in the lower part of the river.

In fact, along the Yangtze River, in addition to the Three Gorges Dam, 23 dams have been completed, 32 are under construction, 46 are under planning.

The topography in the west is high upstream, and downstream in the east. Therefore, the Yangtze River flow is divided into 3 ’steps’, in which the area between the upper steps with the highest difference is considered to be the best place to build a hydroelectric dam.

The Three Gorges Dam is located at a large difference, so the flow of water is very strong, very suitable for running the generator. Meanwhile, the localities in the middle and downstream have flat terrain, do not have big differences, and are not eligible to build big dams like Tam Hiep.

Another factor is the construction of a dam to prevent flood water, as the reservoirs in the dam need to be large enough to contain the flood water. In Tam Hiep, for example, people take advantage of the high terrain on both sides of the dam to prevent floods.

In the middle and lower regions, the terrain is low, so it is difficult to prevent floods even with a big dam like Tam Hiep. Once floodwaters arrive, the entire area surrounding the dam will be submerged in water, causing flooding there.

Page QQ said, the construction of upstream dams mainly to prevent floods, once the flood situation is stable will gradually discharge floods in the dam reservoir. Of course, the discharge should not exceed the drainage capacity of the downstream, to avoid the occurrence of flooding.

And although the lower Yangtze region does not have the capacity to build large dams to prevent floods like Tam Hiep, these localities are close to the sea. As long as local governments do well in preventing disaster such as establishing early warning facilities to control floods, the impact of rain and floods will be minimized.