Pictures: Water blast experiment at Glen Canyon Dam
Huge amounts of water are being released from the Glen Canyon Dam for an experiment, so that tonnes of sand can be washed down the Colorado River.
Wow! Water blasts out of massive tubes at the Glen Canyon Dam in Arizona state, USA.
Loads of water is being released for an experiment so that tonnes of sand can be washed down the Colorado River.
A dam is a manmade barrier created to stop the flow of water. The Glen Canyon Dam stores and releases water from Lake Powell - it uses the water power to generate electricity and it also helps to control flooding.
It's hoped the sand will create beaches and improve plant and animal habitats along the Colorado River.
The experiment began on Monday and is due to last five days.