China yesterday blocked the flow of the Yangtze River by closing gates at the massive Three Gorges Dam and began to fill up what will be the world’s largest reservoir. It’s a joyous occasion for government engineers and Communist Party faithful who have long touted the coming benefits of hydroelectric power and flood control, and it’s a devastating blow to environmentalists and up to 2 million people who will eventually be displaced by the rising waters. The reservoir will grow to be 385 miles long and a mile wide and will submerge two cities and 1,352 villages. Enviros warn that it’s poised to become a cesspool, as the settlements to be flooded contain decades worth of accumulated trash and toxic waste, and Chongqing and other cities along the reservoir’s shores will dump billions of cubic feet of industrial waste straight into the water each year. Small cracks have already been uncovered in the dam, and a handful of people have been arrested for providing substandard construction materials. Many residents of the area are refusing the leave. “The water is going to take my livelihood away from me,” said 60-year-old farmer Du Xiaoshan, whose fields will be submerged. “Farming oranges is all I know.”