Fears about pollution from a gas-extraction technique called hydraulic fracturing have landed the Upper Delaware River on the top spot in an environmental group's ranking of the 10 most endangered U.S. rivers.
The annual list is part of a media campaign by the group American Rivers aimed at focusing attention on environmental threats to waterways.
Politics -- as opposed to water-quality data -- determine the rankings. A river lands on the list based on what the group considers to be major, upcoming policy or permitting decisions, the significance of the threat and the degree to which the action would exacerbate or alleviate the stresses of climate change.
The usual culprits that push up a river's ranking include proposed dams, water diversions or management plans.
What's remarkable this year -- the ranking's 25th anniversary -- is the prominence of hydraulic fracturing, which landed two rivers in the top 10 list. It's the reason behind the No. 9 ranking for the Monongahela River, which spans Pennsylvania and West Virginia.
Chalk up these dubious honors as a sign of the escalating conflict over whether hydraulic fracturing deserves federal regulatory scrutiny.
The Upper Delaware provides drinking water to 17 million people in Pennsylvania and New York. Both the Upper Delaware and the Monongahela straddle the natural gas-rich Marcellus Shale formation, where two companies have proposed developing up to 17,000 gas wells, according to American Rivers.
"Folks have known this resource has been here for a while, but it hasn't had as much attention from the industry until now," the group's Jessie Thomas-Blate said of the gas deposits.
The Upper Delaware edged out last year's top-ranked Sacramento-San Joaquin River Delta, ground zero for California's water wars, which is this year's No. 2.
Unlike the obvious problems that attend oil spills, there are no conclusive studies that have directly linked hydraulic fracturing to groundwater pollution. The decades-old practice involves blasting millions of gallons of water, sand and chemicals deep underground to free trapped natural gas. Environmentalists fear what's not known: exact ingredients of the injected mix of chemicals.
Although there have been documented spills and other incidents, pollution problems stemming from fracturing have yet to rise to catastrophe-level and, as such, efforts in Washington to clamp down on the practice have waxed and waned.
A U.S. EPA investigation is under way, but last week Rep. Diana DeGette (D-Colo.), a persistent critic of the practice, introduced and then withdrew an amendment to water legislation that would have required full disclosure of fracturing chemicals (Greenwire, May 26).
Gas companies are nervous. Fearing that tougher water laws might impede drilling in the Marcellus Shale, Exxon Mobil Corp. inserted an out-clause into a pending $41 billion deal to purchase driller XTO Energy.
"We need to study the questions of the risk to the drinking water of 17 million people before we wind up with a Gulf-like disaster," Andrew Fahlund, American Rivers' senior vice president of conservation, said in a reference to the BP PLC oil spill in the Gulf of Mexico. "A great deal of study needs to take place before citizens can be assured its safe."
Other rivers making this year's top 10: (No. 3) West Virginia's Gauley River, which faces mountaintop-mining threats; (No. 4) North Carolina's Little River for a proposed dam; (No. 5) Iowa's Cedar River, threatened by flood-management practices; (No. 6) the Upper Colorado River, for water diversions; (No. 7) Chetco River in Oregon, because of mining; (No. 8) Teton River in Idaho for a dam proposal; and (No. 10) Coosa River in Alabama, also threatened by dams.
More details are available at the American Rivers website.