'Big Muddy' Is Most Endangered River

April 11, 2001 -- In May of 1804, Meriwether Lewis and William Clark set out on an expedition across the Louisiana Territory. They traveled much of the way on a 2,500-mile, slow-moving river that was quickly dubbed the "Big Muddy."

Today, the mighty Missouri River — part of the longest river system in the United States — is in trouble. According to the environmental group American Rivers, which today released its 16th annual list of the country's most endangered rivers, the Missouri is in the worst shape, followed by the Canning River in Alaska and the Eel River in California.

The group says the main threat to the Missouri River are six dams that are pushing several river wildlife species to the brink of extinction, all for the sake of a small amount of barge traffic. American Rivers has called upon government agencies to modify the operations of these dams.

"The [Army] Corps [of Engineers] continues to run the Missouri River to benefit ahandful of barges," says Rebecca Wodder, president of American Rivers. "It is time to prevent species extinction, tap the Missouri's great economic potential for recreation and tourism and meet the modernneeds of riverside communities."

The Environmental Protection Agency did not immediately respond to calls from ABCNEWS.com seeking comment on the report.

Electricity Generation Takes Its Toll

Wodder attributes the devastating environmental damage to many of the rivers on the list to outdated ways of developing and using energy. Power plants and the quest to find more fossil fuel in areas near some of these rivers are primarily to blame for the dramatic increase of pollutants that are lethal too the rivers' wildlife populations, she says.

"Coal-fired plants … are the largest uncontrolled source of toxic mercury into the environment," Wodder says. “Mercury contaminates fish eaten by more than 7 million Americans, despite health advisories in 40 states."

Acid rain, the transfer and deposit of pollutants and fertilizer through rainfall, is also a major factor that has contributed to the endangerment of many of the nation’s rivers and surrounding ecosystems. The Paine Run River in Virginia’s Shenandoah National Park — which ranks as 11th on the list — is one victim succumbing to acid rain, Wodder says.

"Like more than 1,300 other mountain streams in the Middle Atlantic, [Paine Run] is succumbing to acid rain caused by antiquated coal-burning plants in the Ohio and Tennessee valleys that are exempt from the Clean Air Act," she says.

Wodder says government and industry together need to become more responsive to the problem.

"While we’re still using fossil fuel and hydropower, let’s make sure that we operate those facilities in a way that minimizes the impacts," Wodder says. “The impacts on the rivers have been ignored for too long when … those impacts are often felt first and worst on our nation’s rivers.

"We would like to see a policy that takes a balanced approach and considers all of the impacts that are created by energy developments in use," she says.

The Missouri River has topped this list at least five times in recent years. However, most rivers are taken off the list within one year, says Eric Eckl, a spokesman for American Rivers, because the group finds publicity from their studies is able to sway public and private clean-up resources.

Missouri River's Damage Widespread

The Missouri's major dams are almost 90 miles away from North Dakota’s capital, Bismark. But Jonathan Bry, conservation program coordinator for the Dakota Chapter of the Sierra Club there, points out that several hundred miles of the river's banks have been rip-wrapped, or channeled. This causes the river to become narrower and faster in parts, which in turn, affects fish populations, he says.

"If you're stabilizing the banks of the river, it's getting narrower, and that reduces shallow areas necessary for spawning. The fish and their eggs get swept down the current," Bry says.

The stripping process also involves scooping out swathes of vegetation, which alters the region's habitats, he says.

"In North Dakota, the primary goal is to work on a local level with zoning boards and come up with unified setback regulations," Bry says. "We want to preserve the public ownership values of the river, and keep its banks stable."

ABCNEWS Radio and ABCNEWS.com's Melanie Axelrod contributed to this report.