Longtan Dam is a large roller-compacted concrete (RCC) gravity dam on the Hongshui River in Tian'e County of the Guangxi Zhuang Autonomous Region, China, a tributary of the Xi River and the Pearl River. The dam is 216.2 metres (709.3 ft) high and 849 m (2,785 ft) long; it is the tallest of its type in the world. The dam is intended for hydroelectric power production, flood control and navigation. The dam contains seven surface spillways, two bottom outlets and an underground power station. The Longtan ship lift, part of the dam complex, will be the tallest ship lift system in the world.