The conservation group American Rivers has updated its yearly listing of the country's top 10 at-risk rivers, something it has tracked for more than a quarter of a century. Following is the list for 2013, along with each river's specific threat and what is at risk.
The Colorado River supports people and animals across seven states.
Threat: Outdated water management. At risk: Recreation economy, water supply, and wildlife habitat.
Flint River, flowing below Bainbridge, Ga.
Many tributaries in Georgia's Flint River (which provides water to more than 1 million people) are completely drying up.
Threat: Outdated water management. At risk: Water supply for communities, farms, recreation, and wildlife.
San Saba River
On the upper boundary of Texas' Edwards Plateau runs the San Saba River. Unregulated pumping by irrigators is harming the river.
Threat: Outdated water management. At Risk: River flow for ranchers, citizens, and lakes.
In 2005, portions of the Little Plover dried up for the first time.
Wisconsin's Little Plover River runs six miles and then joins the Wisconsin River. Groundwater withdrawals have reduced its flow, and over the last 10 years parts of it have gone dry more than once.
Threat: Outdated water management. At Risk: Fish habitat and water supply.
Wylie Dam sits along the Catawba River in York County S.C.
North and South Carolina share the Catawba River, which supplies many in the southeast with water and recreation.
Threat: Coal ash pollution. At risk: Drinking water and recreational enjoyment.
A view of Boundary Waters, between Minnesota (right), and Ontario, Canada (left)
Minnesota's Boundary Waters Canoe Area Wilderness covers more than 1 million acres. The South Kawishiwi River flows into the Boundary Waters and is threatened by mining activity.
Threat: Copper and nickel mining. At risk: Recreation economy, drinking water and wilderness.
The Swann Bridge spans the Locust Fork of the Black Warrior River in Cleveland Ala.
Alabama's Black Warrior River is a key source of drinking water that is threatened by mining activity.
Threat: Coal mining. At risk: Drinking water quality and fish and wildlife habitat.
Rough and Ready Creek in Southern Oregon
Oregon's Rough & Ready and Baldface creeks are tributaries of the Wild and Scenic Illinois and North Fork Smith rivers. They're threatened by nickel mining activity.
Threat: Nickel mining. At risk: Rivers, wilderness, botanical diversity and recreation.
A view of the Kootenai River from the Boundary Connections project in Idaho.
Shared among British Columbia, Montana and Idaho, the Kootenai River is home to rare fish species and supports grizzly bears and caribou. It's threatened by mining activity.
Threat: Open-pit coal mining. At risk: Water quality and survival of rare fish and wildlife.
Flowing amid Nebraska, Wyoming and South Dakota, the Niobrara River is a hotspot for fishing, canoeing and wildlife. Its lower portion is a federally protected Wild and Scenic River.
Threat: Sediment build-up and flooding. At risk: Property, crops and public safety.