WUHAN, June 18 (Xinhua) -- Wednesday marks the 22nd anniversary of the operation of the ship locks of the Three Gorges Dam, the world's largest hydropower project.

Over the past 22 years, the ship locks have handled over 1 million vessels, over 12.2 million passenger trips, and facilitated a total freight volume of 2.24 billion tonnes, the Three Gorges Navigation Administration said on Wednesday.

The Three Gorges project is a multi-functional water-control system, consisting of a 2,309-meter-long and 185-meter-high dam, five-tier ship locks on the north and south sides, and 34 turbo-generators with a combined generating capacity of 22.5 million kilowatts.

As an essential part of the project, the ship locks have maintained safe and efficient operations since they opened navigation to social vessels on June 18, 2003. The annual freight volume has increased from an initial 34 million tonnes to the current peak of 169 million tonnes, and has surpassed the 100-million-tonne threshold for 11 consecutive years and exceeded 150 million tonnes for three years in a row.

To tackle the challenge of the ship locks' limited design capacity compared to the growing freight demand, the administration has taken several measures to optimize the navigation procedures and improve the maintenance efficiency. ■