The Environmental Protection Agency has decided to veto construction of the Two Forks Dam in Colorado, the largest non-federal water project in the West, it was reported Friday.

The Washington Post said EPA Administrator William K. Reilly is expected within a few days to announce a decision to block the billion-dollar dam, which the city of Denver had sought to increase water supplies for its suburbs.But EPA officials said Friday that while action will be taken soon on a review board's recommendation that no dam be built at the site, no decision has yet been made.

The officials, who commented on condition they not be identified, said Riley will not make the decision himself but has delegates working on a document" but added: "Until it is final it is inappropriate to tell you what's in it."

The dam has been the focus of an intense battle between environmentalists and supporters of increased development.

The proposed project called for flooding much of Cheesman Canyon, a wilderness area between two forks of the South Platte River.