BEIJING-A photographer used a drone to capture spectacular images of cascades of water gushing from a dam in central China, an annual event attracting thousands of tourists.

Water thundered from channels built into the Xiaolangdi Dam on the Yellow River in the central province of Henan, producing huge waterfalls, waves and steam.

The release is part of efforts to flush silt from the bottom of a reservoir behind the dam. The Yellow River is famously silty - hence its name.

The huge cascades pull in photographers each year, but a bird’s eye view of the plumes of water was made possible Tuesday by a drone which revealed the huge scale of the event - and the giant plumes of mud entering the river below the barrage.

In an attempt to attract tourists, the nearby city of Luoyang puts on a “wave festival” each year. This year the event will run for a week, with water released at set times each day and air-conditioned buses laid on for viewers.

The Xiaolangdi Project was completed in 2000 at a cost of $3.5 billion and generates around five billion kWh of electricity a year.

China has undertaken an unprecedented dam building spree in recent decades, including the Three Gorges Dam, the world’s largest in terms of capacity. Only one of China’s major waterways - the remote Nu River in Yunnan province - remains undammed.

Critics say the facilities damage aquatic life and have required the relocation of hundreds of thousands of people with little compensation.