RELEASE: Half the Length of All Western Rivers Harmed by Human Development, CAP Analysis Says

Washington, D.C. — About half of all river miles in the West have been damaged by human development, according to a first-of-its-kind analysis of how these waterways are affected by dams, abandoned mines, development in floodplains, irrigation, and other activities. That totals 140,000 river miles—enough to circle the Earth nearly six times.

The groundbreaking Disappearing Rivers website is a project from the Center for American Progress and Conservation Science Partners that provides a new tool to measure—at a micro and macro scale—how rivers in 11 Western states have been affected by human use.

“Every river and every community is different, but we need to heed the warnings we see in this report about stresses on our rivers – including climate change, development, and abandoned mines,” said Sen. Tom Udall (D-NM), who is a leader in the fight to protect public lands and reform the nation’s antiquated 1872 Mining Act. “Everyone in America has a stake in the future of our Western waterways. If we lose our rivers, we lose our heritage, we threaten our economy, and we put major cities and states at risk.”

Changes to a river’s flow, whether from dams or other man-made structures, are a serious impediment to water flow in the West. Less than 80 percent of river miles are flowing close to their natural levels, and the length of a river today is reduced by 84 percent from its natural state.

“From the roaring Colorado River to the iconic Rio Grande, most of our majestic waterways are shadows of their wild, free-flowing pasts,” Nicole Gentile, the project’s author and deputy director of the public lands project at the Center for American Progress. “The poor and deteriorating condition of rivers and streams poses a grave threat to drinking water supplies, wildlife, and a Western economy for which water is the lifeblood.”

Some states have essentially no semblance of natural major rivers left. In Utah, for example, more than 99 percent of major rivers, including the Colorado River and the Green River, are altered from their natural state.

The project also mapped active and abandoned mines in the West and their aggregate effects on water quality further downstream. By the time the Colorado River reaches Mexico, for example, nearby residents are at risk of pollution from 20,138 upstream mines.

“The Disappearing Rivers project gives policymakers and planners access to data and analysis that can guide smarter decisions about where to build, what to protect, and how to restore the waterways of the West to a more healthy and functional state,” said Brett Dickson, president and chief scientist of Conservation Science Partners, a nonprofit scientific organization that specializes in cutting-edge science data and mapping.

The analysis found that protected public lands play an indispensable but underappreciated role in supporting healthy rivers and streams. Rivers that run through protected lands in the West, such as national parks, are 50 percent more natural than rivers that flow through unprotected areas.

The analysis also shows that rivers and streams play an outsized role in supporting the outdoor recreation economy. Places in the West with the most rivers and streams support a whopping 717 percent more outdoor recreation spending than those with the fewest.

See the Disappearing Rivers project and an interactive map here.

Click below to see state fact sheets:

Arizona
California
Colorado
Idaho
Montana
Nevada
New Mexico
Oregon
Utah
Washington
Wyoming

For more information or to talk to an expert, please contact Sam Hananel at shananel@americanprogress.org or 202-478-6327.