A preliminary federal study has revealed that the dam at Cherry Creek reservoir in Denver, US, is potentially unsafe.

The US Army Corps of Engineers (USACE) study said that whilst the dam, located 32km from the city of Denver, is in no immediate risk of failing, it may not be able to survive a catastrophic flood, and waves from the 356ha reservoir could surge over the top.

A full study is to be completed by USACE in March 2007. It will determine whether the dam will have to be raised or strengthened.

USACE began reviewing Cheery Creek dam in the 1980s and 1990s, but work was halted after a public outcry over the effect that any safety measures might have on surrounding property. But it re-started its review late last year, using precipitation data from a state study completed in 2003.