Water may be crucial for life in the West, but Westerners in 11 states have manipulated and trashed rivers to such an extent that half are now impaired – an impact measured as especially severe in Colorado.

"Disappearing Rivers," an analysis to be unveiled Wednesday in Washington, D.C., identifies the culprits as developers who build along waterways; utility operators who divert water to generate power; cities and irrigators who disrupt natural flows using dams; and industries, such as mining, that are allowed to pollute streams.

In Colorado, water flows in 63 percent of streams and rivers are restricted by dams or development in floodplains, the analysis by California-based Conservation Science Partners determined. In neighboring Utah, virtually no unaltered natural waterways exist.

"We think of rivers as natural and pure. We found there was a high degree of degradation," said CSP senior scientist Dave Theobald, a geographer and conservation biologist who serves on the faculty and conducts research at Colorado State University.

Revitalization of rivers must become a top priority, because healthy, clean waterways are economically and ecologically essential, Theobald said, but the cost will be huge, Theobald said. "It is tremendously inefficient to clean up something. It is more efficient to leave it pure in the first place."

Read the full story from The Denver Post.