The first Europeans to explore America found a land rich in rivers -- some 3.5 million miles' worth of free-flowing waters full of life.
The rivers near Jamestown, Va., were "so stored with sturgeon and other sweet fish as no man's fortune has ever possessed the like," wrote one of Capt. John Smith's companions in 1607. The French Rene-Robert Cavelier, Sieur de La Salle dazzled the court of Louis XIV with his descriptions of the mighty Mississippi in 1682.
Today the James River is tainted with pesticides, sewage and farm runoff. The once-wide Mississippi has been walled in by levees -- a process that began in the 1720s.
Over the past three centuries, dams have tamed about one in every six miles of U.S. rivers, choking off the great runs of salmon, herring and shad that sustained early inhabitants.
Farmers and builders have drained about half of the riverside marshes where winged, webbed and finned creatures dabbled and dived.
And the detritus from a continent's worth of parking lots and pastures taints more than 2 million miles of rivers and streams, rendering them unfit for fishing and swimming, according to the Environmental Protection Agency.
"You could not step twice into the same river," wrote the Greek philosopher Heraclitus 2,500 years ago. "Nothing endures but change."
But American Rivers, an environmental group based in Washington, wants to stop time -- or roll back the clock -- for some troubled waterways.
Each spring the group compiles a list of America's "most endangered rivers." Each body of water the activists single out is near "a public policy decision that is either going to send it down the tubes ... or turn things around," said American Rivers spokesman Eric Eckl.
In this year's list, published this month, the group also took a swipe at the Army Corps of Engineers, which it accuses of "destroying your rivers [and] wasting your money."
Corps dredging and construction projects are the main issues affecting four of the 11 rivers on this year's list, and similar projects have been involved in 60 percent of the rivers included on the list since it began in 1986. Corps officials have defended each of the criticized projects.
This is the conservationists' list of the most endangered waterways of 2002:
No. 1: The Missouri, the nation's longest river, flows from western Montana to its junction with the Mississippi near St. Louis. In 1804, explorers Meriwether Lewis and William Clark rode this watery High Plains highway west into unknown territory on their history-making expedition. Even modern travelers crossing the Missouri might sense that they are crossing the boundary between the heartland and the West.
The activists criticized the Corps' use of dams and locks to control the river's flow, altering the seasonal rise and fall of water levels. A National Academy of Sciences report found that the unvarying flow benefits barges, but deprives endangered fish and birds of essential spawning and nesting sites. The Corps is under pressure from conservationists and some members of Congress to restore a more natural flow pattern.
No. 2: The Big Sunflower meanders in lazy loops past small Mississippi towns such as Indianola, its banks dense with the hardwood trees that have become rare along Southern rivers. About 55 varieties of fish swim in its water, and waterfowl spend the winter in its marshes.
The Corps has proposed construction of the Yazoo Pumps plant, which would drain much of the marshes for farming, and also wants to dredge the river to help move the pumped-out water more quickly. Environmentalists say dredging would release pesticides such as DDT buried in sediments. The Corps says the pesticides can be contained.
No. 3: The Klamath flows through Oregon's arid eastern half through the Cascade Range to the Pacific Ocean. Like most Pacific Northwest rivers, the Klamath once supported abundant salmon runs and a Native American culture that depended on them. The depleted salmon are protected by the Endangered Species Act.
Last summer, amid a drought, water managers held back part of the river's flow for the salmon's benefit. Angry farmers briefly took control of a river lock, diverting irrigation water to their fields.
No. 4: The Kansas River runs roughly parallel to Interstate 70, draining the cattle country west of Kansas City. It is polluted with livestock manure and urban runoff. Environmentalists have sued the state to force a cleanup.
No. 5: Arkansas' White River, falling cold and clear from the Ozark Mountains, supports a popular trout fishery. The White River National Wildlife Refuge is a haven for ducks and black bears.
The Corps of Engineers operates five dams on the river. Environmentalists oppose a Corps proposal to divert river water to irrigate farms.