Xiaonanhai Dam upstream from the Three Gorges Dam. Weng Lida, a former director of the water resources bureau at the Yangtze River Commission, said that senior China Three Gorges executives had succumbed to pressure from the Chongqing authorities. According to the "South China Morning Post", Chongqing's success in overcoming all major obstacles to the dam's construction is attributed to the personal intervention of Bo. The project was strongly opposed by environmentalists, who saw it as a "politically motivated decision". It was highly controversial due to the environmental impact, the high cost-benefit ratio, as well as the secretive decision-making process under Bo. A
Three Gorges Dam spillway gates of the dam might pose a risk of cavitation, similar to that which severely damaged the poorly designed and cavitating spillways of the Glen Canyon Dam in the US state of Arizona, which was unable to properly withstand the Colorado river floods of 1983. However, 163,000 concrete units of the Three Gorges dam all passed quality testing and the deformation was within design limits. An experts group gave the project overall a good quality rating. In order to maximize the utility of the Three Gorges Dam and cut down on sedimentation from the Jinsha River, the upper course