EPA wants further review of water-diversion project to protect Colorado River

Federal authorities say a long-planned project to divert more western Colorado water to growing Front Range suburbs may cause "significant degradation" of already deteriorating ecosystems along the upper Colorado River.

An Environmental Protection Agency review of data used in planning the project found mathematical errors and a downplaying of "critical adverse impacts" from the $270 million project, which Colorado leaders consider crucial for millions of residents.

EPA reviewers cited a separate 2011 state study that documented the disappearance of all native sculpin fish and 38 percent of aquatic insect species over 20 years as a result of existing water diversions.

An EPA document, sent to federal permitting authorities last week, recommends further analysis of the Northern Water Conservancy District's Windy Gap Firming Project to prevent new violations of state water-quality standards and "a more robust monitoring and mitigation plan" to protect the river.

"The EPA has not recommended delaying this project," EPA regional administrator Jim Martin said. "Our recommendations are intended to provide a path forward that also protects the Colorado River."

Read full text: Denver Post