Troubled tributary

Runoff, growth turn the Choptank into Md.'s second-most polluted river

Sun special report

December 09, 2007|By Rona Kobell | Rona Kobell,Sun Reporter

CAMBRIDGE -- It looked like just another beautiful day on the water as Bill Dennison and his crew of biologists pushed off from their pier at the Horn Point Laboratory and sailed toward the mouth of the Choptank River. The sun glistened on the waves. In the distance, craggy, tree-lined peninsulas carved the river into jagged coves that have long been home to crabs and rockfish.

But there were hardly any fishing boats. In fact, hardly anyone was on the river at all.

It soon became clear why. The researchers passed large patches of brownish-white foam - so-called "mahogany tides" where the water is so thick with algae that no light can get through. The tides have killed many of the river's once-lush grass beds, depriving crabs of their nursery habitat. The algae have also led to low oxygen levels that have forced the crabs and fish to go elsewhere.

The signs are everywhere: The Choptank is in trouble.

This Eastern Shore river, which meanders along farm fields and past picturesque towns on its way to the Chesapeake Bay, recently ranked as the second-most polluted river in the state. Only the Patapsco, which runs through Baltimore City, was worse.

Dennison, a vice president at the University of Maryland Center for Environmental Science, oversaw the rankings. It was with no pleasure that he gave the Choptank a D-minus.

"It has visibly changed," Dennison said, "and now the data support that it has functionally changed."

In the nearly 25 years since Maryland, Pennsylvania and Virginia signed a historic agreement pledging to clean up the Chesapeake Bay and its rivers, the Choptank has not only failed to improve, but, by many measures, it has also gotten worse. The river is being choked by pollution from the region's farms and many new housing developments.

The amount of nitrogen flowing into the Choptank was twice as high in 2005 as it was in 1985 - the year measuring began in earnest - according to the U.S. Geological Survey, which monitors the river at its headwaters in Greensboro. In many places, the water's algae content also has doubled, according to the Chesapeake Bay Program, a federal-state partnership. Sediments, too, have deluged the river, further clouding the water.

All the algae are blocking sunlight from nourishing the plants and sea creatures that have long made the Choptank a productive ecosystem. In 1985, the Choptank had 3,561 acres of underwater grasses - key habitat for crabs and small fish and worms. Last year, the river had just 1,092 acres, about a 70 percent loss.

The Choptank's creatures are losing not only their habitat but also their breath.

When algae die and settle to the bottom, they decompose. In the process, they suck up much of the river's oxygen, suffocating the creatures that live on the bottom.

Maryland can't blame other states for the Choptank's problems, because the 68-mile-long river flows almost entirely within the state. And its decline shows why the Chesapeake Bay as a whole is suffering.

Much of the Choptank's pollution is coming from nitrogen-rich fertilizer, which runs off farm fields and into the river after rains.

But growth on the Eastern Shore is also a factor. Since 1980, the nine-county peninsula has added about 100,000 people. The three biggest towns on the river - Easton, Cambridge and Denton - have grown by more than 20 percent, and are expected to expand even more. Such growth leads not only to more waste but also destroys pollution-absorbing open spaces and adds paved surfaces, which create paths for nitrogen from lawns and elsewhere to run into the rivers.

The increasing pollution is frustrating not only to Horn Point scientists, whose lab has provided a front-row seat from which to see the decline, but to many others who live, work and fish along the river.

"What's happened to that river is heartbreaking," said Bill Goldsborough, a senior scientist at the Chesapeake Bay Foundation who for years lived near the river. "Absolutely heartbreaking."

Worst of all, Choptank researchers say, is that the government knows what to do but seems to lack the will to do it.

Better days

The river was in much better shape when Dennison first arrived on its banks in 1987.

Skipjacks still dredged for oysters in front of the laboratory. The young graduate student could swim in the river. Often, he would put on a wet suit and snorkel gear and dive among the river's lush grass beds, which were filled with crabs and fish. Back then, the watershed was still largely rural.

For Dennison, now 53, it was a time of great optimism. The Chesapeake Bay Agreement, signed in 1983, had made a bold promise to save the bay through voluntary measures.

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