Two polluted tributaries of the Chesapeake Bay, one urban and the other rural, rank among the most threatened rivers in North America, a national conservation group said yesterday.
Runoff from Washington-area streets fouls the Anacostia River, and pollution from Pennsylvania farms has put the Susquehanna at risk, said American Rivers, a Washington-based organization.
The Anacostia, which flows from Maryland through Washington, and the Susquehanna, the bay's largest freshwater artery, made the group's list of 25 waterways considered "in serious decline."
The Anacostia, appearing in the annual ranking for the first time, made the top 10 -- the "endangered" group. The Susquehanna was a repeater in the bottom 15, the "threatened" category.
"By making the public and political leaders aware of just how poisoned, dredged, dammed and overdeveloped our rivers are, the prospects for protecting and restoring [them] improve immeasurably," said Kevin Coyle, American Rivers president.
Topping the group's sixth annual list of endangered waterways is the Rio Grande, which flows for 2,000 miles through three western states and forms the border between Mexico and Texas.
The conservation group said that some parts of the Rio Grande are "a virtual cesspool," fouled by untreated residential sewage and by industrial pollution from American-owned factories on the Mexican side.
Other endangered waterways: the Columbia and Snake rivers in the Pacific Northwest, where hydropower dams and logging have decimated salmon stocks; and the Everglades, Florida's "river of grass" whose waters have been diverted for farming and municipal use.
The Anacostia was ranked fourth on the endangered list because it typifies the problems plaguing all urban waterways, Mr. Coyle said.
It is Washington's "forgotten river," flowing through the capital's poor neighborhoods and rail yards on its way to the more celebrated Potomac.
The Anacostia has endured nearly four centuries of abuse, beginning when English settlers cleared its banks in the 1600s to grow tobacco.
Though sewage treatment has helped, the river still suffers from a legacy of neglect and degradation. Its wetlands were filled decades ago and its banks straightened and armored with concrete in the name of flood control.
More recently, suburban development has paved over more than one-fourth of the Anacostia's watershed and polluted the river with runoff laced with organic matter, oil and pesticides.
Its fish are contaminated with two toxic chemicals: PCB's, a one-time lubricant; and chlordane, once widely used to control termites in homes.
"The Anacostia is a good example of an urban river that's been worked and worked and worked," Mr. Coyle said. Yet there is hope, he said, because turtles, ducks, egrets, great blue herons and other wildlife can be seen along its banks.
Maryland and the District of Columbia first pledged to restore the Anacostia in 1984, and the state has spent more than $2 million since then to help control runoff in the Washington suburbs.
As for the Susquehanna, Mr. Coyle said that his group now sees polluted runoff from farms as the main threat to the river, which flows 444 miles through New York and Pennsylvania before reaching Maryland at the northern end of the Chesapeake Bay.
Because of manure-laden runoff from dairy and hog farms, the Susquehanna delivers 40 percent of the nitrogen fouling the bay, and 21 percent of the phosphorus.
Those nutrients spawn massive growths of algae, which harm fish and underwater plants.