Bay Pollution Progress Overstated

They blamed the more optimistic model figures for shrinking political support for more rigorous anti-pollution measures.

"It's sucked the public outrage out of the system," said Howard Ernst, author of "Chesapeake Bay Blues" and senior scholar at the Center for Politics at the University of Virginia. "If you are told year after year that things are getting better, what's the incentive to make the necessary changes?"

Theresa Pierno, vice president of the Chesapeake Bay Foundation, a watchdog group, said the computer model and the Bay Program have something in common. "The model is extremely over-optimistic -- and the rhetoric continues to be very optimistic," she said. "But the improvements that we have seen in the bay have been very, very small."

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 offset by pollution created by the rising population in the bay's vast watershed.

"As we speak, Virginians are working diligently to meet the commitments of the Chesapeake Bay agreement," Virginia Gov. Mark R. Warner (D) said at a meeting of bay state leaders in December.

But exactly what the cleanup goals are, and how to measure their achievement, has proven a problem from the start.

In the widely publicized 1987 agreement, the District, Maryland, Virginia and Pennsylvania promised to reduce the amount of nutrients flowing into the bay by 40 percent by the year 2000.

To the consternation of several involved scientists, the members of the Chesapeake Bay Program soon after interpreted the promised reductions to exclude pollution from cars and other sources. The agreed-upon 40 percent reduction was cut to 20 percent for nitrogen and 31 percent for phosphorus.

The Chesapeake Bay Program has reported its progress against those goals primarily by citing the results of its computer model, though officials also review water monitoring reports as another means of examining the bay.

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.