"Bay Pollution Progress Overstated: Government Program's Computer Model Proved Too Optimistic" is the headline to this page one story today in the Washington Post. Some quotes:
At news conferences, on its Web site and in its regular publications, the government agency leading the cleanup of the Chesapeake Bay has documented more than a decade of steady progress.The story includes this graphic on measuring the Bay's pollution.The Chesapeake Bay Program has reported that the flow of major pollutants from rivers into North America's largest estuary has declined nearly 40 percent since 1985, bolstering the claims of politicians in Virginia, Maryland, Pennsylvania and the District that they were "saving the bay" and helping the states fend off criticism and lawsuits from environmentalists.
Those reports, however, significantly overstated the environmental achievements. The estimates of pollution reduction were based on a computer model -- not water samples -- that program officials now say was distorted by overly generous assumptions. * * *
U.S. Geological Survey water monitoring data from the mid-1980s through 2003, requested by The Washington Post, indicate that observed concentrations of the two targeted pollutants, nitrogen and phosphorus, showed no decline in most of the major rivers spilling into the bay. * * *
Most of the nitrogen and phosphorus entering the bay from the 64,000 square miles that drain into it come from farm fertilizer, animal waste, sewage treatment plants and air pollution caused by cars, which eventually drops into waters and heads to the bay.
Once there, the chemicals serve as nutrients that set off algae blooms, which block sunlight from the sea grass and creatures on the bay bottom, while also starving them of oxygen.
As part of the cleanup, the states have pushed for the retrofitting of sewage treatment plants, encouraged farmers to minimize excess fertilizer and animal waste flowing into streams and groundwater and cautioned against long-distance automobile commuting.
One of the program's most significant achievements was the phosphate detergent ban that went into effect in the bay states and the District between 1985 and 1990, a measure believed to have yielded significant phosphorus reductions. This spring, too, Maryland legislators passed a $2.50 monthly surcharge on every homeowner in the state -- the "flush tax" initially proposed by Gov. Robert L. Ehrlich Jr. -- to pay for upgrades to wastewater treatment plants.
Those efforts, however, are countered by pollution created by the rising population in the bay's vast watershed. * * *
The model estimates the amount of pollution flowing into the bay based on the various land uses in the vast watershed. Forested land is judged to contribute relatively little to the problem; agricultural and urban lands contribute the most, officials said.
"It is the Cadillac of watershed models across the world," said Christopher S. Conner, director of communications for the Chesapeake Bay Program.
The model is useful, bay officials said, because it can take variations of rainfall and other factors into account. Even scientists who question its use for measuring progress credit the model with being well-constructed and useful for prediction.
But some scientists and other experts on the bay said the model is the wrong tool for reporting bay pollution because it relies on so many assumptions and because it continues to suggest more progress than water monitoring reports.
The Chesapeake Bay Program's revised computer model currently reports that phosphorus pollution has dropped about 28 percent since 1985 and that nitrogen pollution has dropped about 18 percent.
But according to the U.S. Geological Survey data, the observed concentrations of those chemicals flowing into the bay from the major rivers has changed little.
Here is the website of the Chesapeake Bay Program: America's Premier Watershed Restoration Partnership.
Posted by Marcia Oddi at July 18, 2004 10:34 AM