The Jinping's vertical relief and the Yalong River's elevation drop from one side to the other make it an optimal source of hydroelectric energy. The Jinping-I Dam, on the west side of the Jinping Mountains, is the tallest dam in the world at high. The Jinping-II Dam, a little further downstream, diverts the water of the Yalong River nearly under the Jinping Mountains to the east side of the bend. More than 13.2 million m3 of earth was excavated for the construction of Jinping-II's power station below the mountains. A total of seven tunnels were bored through the Jinping Mountains at depths up to beneath the mountain peaks. This included four water diversion tunnels, two auxiliary tunnels, and one construction drainage tunnel.