World's largest hydroelectric dam ushers in largest flood peak
Updated 15:04, 20-Aug-2020

The Three Gorges Dam in central China's Hubei Province on Thursday ushered in the largest flood peak since the construction of the reservoir, according to local authorities.

At 8:00 a.m. Beijing Time, the Three Gorges Reservoir saw an inflow of 75,000 cubic meters per second. Eleven sluice gates were opened on Thursday with a discharge flow of 49,400 cubic meters per second. 

Read more: Live: Three Gorges Dam discharges its largest flood peak 

The Three Gorges Dam is the world's largest hydroelectric dam. The dam, which was completed in 2006, was designed for a maximum water level of 175 meters. 

Increased discharge from the dam following heavy rains since July has effectively alleviated the flooding pressure on the downstream cities of Yangtze River in Hubei and Anhui provinces. Through multiple rounds of storage and release, total water storage of the dam has reached 18.2 billion cubic meters during this flooding season.

July 2, 2020: Three Gorges Dam opens three sluice gates

The dam opened three sluice gates to discharge floodwater during the first flood of the Yangtze River this year. 

On that day, the inflow of the Three Gorges Reservoir was 53,000 cubic meters per second and the outbound flow was 35,500 cubic meters per second. The dam effectively intercepted part of the flow of upstream water.

Three Gorges Reservoir stored approximately 2.5 billion cubic meters of floodwater on that day.

July 19, 2020: Three Gorges Dam opens seven sluice gates

On the 19, the flood discharge was gradually upgraded to seven. There were five flood discharges at 8 a.m., another at 9:40, followed by another at 11 a.m..

The second flood of the Yangtze River passed the Three Gorges Dam smoothly.

At 12:00 on the same day, the water level of the Three Gorges Reservoir was 163.81 meters, the inflow flow was 54,000 cubic meters per second, and the outflow flow was 40,000 cubic meters per second.

July 22, 2020: Three Gorges Dam opens six sluice gates

To ensure the safety of the Jingjiang dyke, the Three Gorges Dam opened six flood discharges, which effectively reduced the flood control pressure on the middle and lower reaches of the mainstream. 

The reservoir held approximately 8.8 billion cubic meters of floodwater on that day.

July 26, 2020: Three Gorges Dam attenuated the flood peak by 36.7 percent

At 14:00 on July 26, affected by heavy rainfall in the upper reaches of the Yangtze River, the inflow in the Three Gorges Reservoir reached 50,000 cubic meters per second, ushering in the Yangtze River's No. 3 flood in 2020. 

The peak flow at 14:00 on July 27 reached 60,000 cubic meters per second, attenuating the flood peak by 36.7 percent.

The key aspects of the Three Gorges Project in the comprehensive flood control system of the Yangtze River are reflected in its location and its effectiveness. 

The Three Gorges Project is located at the mouth of the Xiling Gorge above Yichang, stopping the floods from the upper reaches of the Yangtze River into the middle and lower reaches of the plains, and can effectively control and reserve the floods in the upper reaches of the river.

This mega-dam aims to do flood control, power generation, and also serves for shipping, and water replenishment. But flood control is the "core capability" of the dam, and it is also the original intention behind its construction.

The Three Gorges Project has installed the world's largest flood discharge sluice gate. The maximum discharge capacity of the dam exceeds 100,000 square meters per second, equivalent to the amount of water poured in 40 Olympic swimming pools in one second.