The north ship lock of the Yangtze River's Three Gorges Dam in central China's Hubei Province resumed operation on April 5 after a 45-day maintenance, 14 hours ahead of schedule. The scheduled maintenance of the north ship lock at the world's largest hydroelectric project began in February. There are two five-tier ship locks and a boat lift for navigation through the Three Gorges Dam, which are an important hub on the Yangtze River, the country's longest waterway.