Satellite images capture China’s Yangtze river dams discharging floodwater

Images captured by NASA’s Operational Land Imager (OLI) on Landsat 8 satellite shows floodwater from reservoirs in the Yangtze river being discharged after excess rain since the onset of the monsoon beginning June 1, 2020.

The flooding in the Yangtze River Basin has displaced millions.

The flood waters  was being held, or “absorbed,” by 2,297 reservoirs in the region, including the one behind Three Gorges Dam. In an attempt to regulate the flow of floodwater, dam operators can discharge water through spillway gates.

Those gates were opened on June 30, 2020 and captured by an earth observatory satellite of NASA.

NASA Landsat 8 captures image of the Gezhouba Dam spilling water on June 30, 2020
NASA Landsat 8 captures image of the Three Gorges Dam spilling water on June 30, 2020

Images show the spillway gates of the Three Gorges Dam and the Gezhouba Dam.

Water was seen moving through the gates of the Three Gorges Dam — 2,300 metres long and 185 m high — to the smaller Gezhouba Dam, around 26 kilometres southeast.

The water around the spillway gates of the dam appears to be whiter because of the way downstream water reflects light. The images were acquired during the first major flooding of the monsoon. A second wave of flooding, referred to as the ‘No. 2 flood’ by local media, hit the region in July.

Continuous adjustments were made by dam operators to the water outflow from the reservoirs at the time of flooding.

Water level went up to a record 164.18 m in the Three Gorges Dam July 19, according to the Three Gorges Corporation that runs the dam. The previous high level was at 163.11 m, during the flood season, since the dam became fully operational in 2012.

The Yangtze River is Asia’s longest, winding 6300 kilometers (3,900 miles) through China. Together with its network of tributaries and lakes, the river system has undergone significant development as a means to generate power, store water for drinking and irrigation, and control flooding.