‘This is truly an historic milestone for the Colorado River, Grand Canyon National Park and the United States Bureau of Reclamation,’ said Salazar. ‘It was an honour to open the door to a new era for Glen Canyon dam operations – a new era in which we realise that the goals of water storage, delivery and hydro power production are compatible with improving and protecting the resources of the Colorado River.’

The protocol aims to better distribute sediment to conserve downstream resources, while meeting water and power needs and allowing continued scientific experimentation, data collection and monitoring on the river. It is built on more than 16 years of scientific research and experimentation conducted under the Glen Canyon Dam Adaptive Management Programme. In co-operation with five interior agencies, the release was designed to take full advantage of sediment deposited by Colorado River tributaries as a result of recent rainstorms and monsoons.

With the Glen Canyon power plant running at full capacity, Secretary Salazar opened the river outlet tubes at noon, releasing additional flows that increased throughout the day until a maximum release of approximately 1197m3/sec was reached. These releases will continue for five days.

‘Favourable sediment conditions in the system only occur periodically so the ability to respond quickly and make the best use of those deposits when the time is right is essential,’ said Anne Castle, Assistant Secretary of the Interior for Water and Science. ‘Today’s experimental release under the new protocol represents a significant milestone in our collective ability to be nimble and responsive to on-the-ground conditions for the benefit of downstream resources.’