Three Gorges Dam. Landsat satellite image of the Yangtze River in Sandouping, Yichang, China, in 2006, the year construction of the Three Gorges Dam (right) was completed. The Dam is the largest hydroelectric power generator in the world. Construction started in December 1994 and it is expected to be fully operational by 2011. At its fullest the reservoir covers over 600 square kilometres. Nearly two million people were displaced to make way for the rising water levels behind the dam.