It was constructed in 1958, and at the time it was the 3rd largest reservoirs in Asia and the largest in China. 160,000 residents were relocated to make way for the reservoir. The ruins of the ancient city of Junzhou () were also flooded. During filling of the reservoir between 1970 and 1973 several reservoir
induced earthquakes were detected up to a 4.7 magnitude shock. After the reservoir was completely filled, no further induced tremors were detected. Between 2005 and 2009, the dam was raised to facilitate the connection to the
South-North Water Transfer Project. By 2014 the water level reached its new designed height of 170 meter, from the original 157 meter. The water surface area was expanded from 700 to 1,000 km² and the storage capacity from 17.45 billion cubic meters to 29.05 billion cubic meters. Over 345,000 people had to be relocated to allow this expansion. == Ecology ==