U.S. authorities started a man-made flood in the Grand Canyon Wednesday in an attempt to help the canyon's ecosystem.

Secretary of the Interior Dirk Kempthorne pulled a lever releasing water from the Glen Canyon Dam, which regulates the flow of the Colorado River. He said the flooding is meant to help redistribute sediment deposits to rebuild beaches downstream.

Kempthorne said the water is being released at a rate that would fill the Empire State Building - New York City's tallest skyscraper - in 20 minutes.

Authorities conducted similar experiments in 1996 and 2004.

Critics of the move say they fear the sudden change will damage wildlife habitats and affect endangered species.

The superintendent of Grand Canyon National Park, Steve Martin told the Los Angeles Times he fears there are non-environmental motives for the flooding, suggesting it is well-timed to aid hydroelectric power producers preparing for high demand during the upcoming summer months.

Some information for this report was provided by AP.