After a decade of work, China will begin filling the reservoir for the Three Gorges dam, a major milestone for the world's biggest hydroelectric project that critics say could bring ecological disaster. The sluicegate of the giant dam at Yichang in the central province of Hubei is due to be shut on Sunday and water from the flood-prone Yangtze river would begin creating a 600-km (365-mile) reservoir, state media said. The water level is expected to reach 135 metres (443 ft) by June 15, the official Xinhua news agency said. Dam officials plan to raise the water level further next year, ultimately submerging 29 million square metres (312 million square feet) of land.