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.
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.
Early signs were encouraging. Sewage treatment plant upgrades during the 1980s and 1990s reduced the amount of phosphorus and nitrogen flowing into the river. In the mid-1980s, Maryland passed a Critical Area Law to restrict shoreline development, as well as a ban on phosphates in laundry detergent. The state also enacted a moratorium on striped bass fishing that allowed the species to revive.
Word spread of the Chesapeake's successes, and the intergovernmental program became a model.
"Back then, it was fresh and new," Dennison said. "They were going to take the steps necessary. They were already backing it up with some actions."
The University of Queensland in Australia was so impressed that, in 1992, it hired Dennison to start its own program to clean up Moreton Bay.
Dennison persuaded the Australians to look at Moreton Bay's physics, its chemistry and its biology. Over the next 10 years, he helped build a program that graded the rivers, established no-take zones for prawns and began work on reducing sewage pollution.
In 2002, after a decade away, Dennison returned to Horn Point. His first year back, drought hit the state. Without rains to wash in pollution and sediment, the Choptank looked more or less as he remembered it.
But the next year, rains deluged the Shore, sending large amounts of sediment and pollution into the river. Dennison stopped swimming in it. He wouldn't let his kids swim, either.
"I came back after 10 years, and I felt like, 'What happened?'" Dennison recalls. "It's sort of like watching children grow up. When you're there every day, you don't notice all the changes. But when you don't see it on a day-to-day basis, it really hits you."
How it declined
Scientists know what happened while Dennison was gone.
The Choptank is one of the bay's most studied rivers. Horn Point researchers are frequently working in the water. The U.S. Geological Survey monitors the Choptank where it begins at Greensboro; the Maryland Department of Natural Resources measures pollution in the rest of it. And the U.S. Department of Agriculture has studied the river for more than a decade.
The data show that nitrogen pollution has been generally on the rise since 1985. Algae, too, have been increasing, while grasses and water clarity have been decreasing. Over the past two decades, the Choptank has lost most of its oysters to disease and over-harvesting, depriving the river of its great pollution filters.
There are years, such as in 2002, when the water quality improves because of drought, but any gains are quickly eroded when weather patterns return to normal.
Much of the pollution comes from farm fertilizer. In 1970, Choptank farmers were applying nine times as much fertilizer to their lands as they did in 1950, according to Horn Point scientist Tom Fisher. Applications have stayed steady since then.
Fisher says that, as food becomes ever cheaper, farmers look for ways to increase their yield to stay in business. The extra fertilizer eventually flows into the river. That can happen quickly, as when rains carry it into water, or slowly, as when the nitrogen leaches into groundwater and then seeps into the river. So, Fisher says, even though fertilizer loads haven't increased since 1990, some pollution from past decades is coming into the river only now.
But the big change since Dennison left was the suburbanization of the watershed.
Once rural hamlets, the towns of the Choptank's watershed had become part of the "commutable Shore" - affordable places to live within a 70-mile drive of Baltimore, Annapolis and Washington. Retirees, too, bought up thousands of condos and single-family homes. In 1980, the combined population of Talbot, Caroline and Dorchester counties was fewer than 80,000. In 2005, it was nearly 100,000 and is expected to hit 117,000 by 2020, according to the Maryland Department of Planning.
More residents meant more pollution from cars, more runoff from paved surfaces and more fertilizer from newly sown lawns. It also meant more wastewater - from treatment plants as well as from the many septic systems serving waterfront mansions.
Despite the Bay Agreement's initial promise, restoration has been one step forward and two steps back. New technology can remove much of the nitrogen and phosphorus from sewage. But when the watershed adds population, the result is more sewage - which, though better treated, still leads to more pollution. At the Easton treatment plant, nitrogen levels in 2005 were about 20 percent higher than in 1985, even with the new technology.
"As populations have increased, wastewater flows have gone up, and agricultural applications of fertilizers have loaded up groundwater with nitrate," said Fisher, who has been studying the Choptank since the 1970s. "There is no evidence that water quality has ever improved."
How to fix it
Just as scientists know what happened to the river, they know what must be done to fix it. The solutions, however, have not been regarded as politically feasible.
"Tributary strategy" teams set up by the state have devised action plans for the Choptank and other bay tributaries. Each team is made up of volunteers who do their own research and advise the state on how to clean up the river.
The problem, says Choptank team leader Robert Wieland, is that the state has declined to act on the recommendations.
One of the easiest actions to take for the Choptank, said Wieland, an economist who lives in Trappe, would be to declare a moratorium on harvesting oysters so the remaining bivalves could filter out pollution. Wieland asked the state for a moratorium in 2004, but then-Natural Resources Secretary C. Ronald Franks put him off, saying the state needed to see more research. Political leaders, both Democratic and Republican, have been reluctant to impose a moratorium that could make it harder for the state's few remaining watermen to earn a living.
Wieland's team also asked the state to determine how much more pollution will be generated from each additional house built in the watershed. That way, local officials would know how proposed housing developments would affect the river. The state's environmental planners have not provided that data.
"The people would be justified in asking, 'What the hell are we paying the environmental protection people for?'" Wieland said. "We're just people waving our arms from the back of the room. We're drowned out by money interests and folks that have a position in the bay hierarchy, and they don't have to listen to us."
State tributary strategies manager Mike Bilek is aware of the frustration, noting that team members have quit because the state hasn't implemented their ideas.
"They're very impatient - they want changes now," Bilek said. But while the advocates often want new regulations, Bilek said, "there's always going to be a certain percentage of what we do that is voluntary."
The team's biggest disappointment has been its years-long push to reduce pollution from farm runoff.
Most experts agree that the best way to control farm pollution is to encourage farmers to plant cover crops, which absorb nitrogen when fields are fallow, helping to prevent pollutants from reaching the bay. Though the strategy was identified in the early 1990s, cover-crop money for the entire state hovered around just $2 million a year until recently. This year, it was increased to $8 million - still only a third of what's needed, state officials acknowledge. The General Assembly just approved a new $50 million fund for anti-pollution efforts statewide to help the bay, though lawmakers have not decided how it will be spent.
Along the Choptank this year, farmers have increased their cover crops to 40,000 acres. That's up from about 5,000 acres three years ago but well short of the state's goal of 90,000 for the watershed.
"Has it been frustrating? What else can I say but yes," said Ken Staver, a small-scale grain farmer and watershed scientist who serves on the tributary team.
A 1998 law required farmers to establish nutrient-management plans in hopes of encouraging conservation measures. But the legislation, which passed after significant concessions to the farm lobby, doesn't require farmers to follow the plans. And it's up to the Department of Agriculture, not the pollution regulators at the Department of the Environment, to enforce the law. Last year, the agriculture agency audited only 4 percent of farms to see if they were following their plans.
Louise Lawrence, the department's resource conservation chief, said Choptank-area farmers have among the highest rates of participation in cover crop programs.
"It's not like farmers in that watershed are just burying their heads in the sand," Lawrence said. "We've had hundreds of years of human activities that have damaged the watershed. Agriculture is one of them. ... When you're talking about an ecosystem, you need to look at all the pieces."
Rep. Wayne T. Gilchrest agrees that more regulation isn't the answer.
"I am thoroughly convinced that a farm is 1,000 times better than a shopping plaza," the Eastern Shore Republican said. "And if you place too much of a regulatory burden on an industry that thrives on flexibility, then we're going to turn into Staten Island, and then the Choptank River really will be dead."
But to Fisher, the Horn Point scientist, a mandatory limit for farm pollution is the solution - that, as well as fines for failing septic systems and penalties for people who fertilize their lawns to the water's edge.
"If you made me God, or president, that's what I would do," Fisher said. "I would be the most unpopular person around, but it would force people to say, 'It's my responsibility.'"
Some who live and work on the Choptank prefer to look at what's good about it. Bald eagles have returned, and striped bass still spawn there. Two hatcheries are using river water to grow oysters.
"I wish it was cleaner, but it's not like [a] wasteland," Staver said. "Compared to the Western Shore rivers, it's got a lot of things in it that are working."
Even Dennison sees positive signs occasionally. Cruising past the mahogany tides on a summer afternoon, his crew found a grass bed near Irish Creek. Elated, he put on his wet suit and snorkel gear and jumped into the water, like old times. After a few seconds, he pulled up a handful of flowering sago pond weed.
But he said that could be part of "the dying throes" - when a river shows recovery in one place but seems lifeless in another. That is how a river dies - not all at once but in slow motion, so observers often don't notice what's lost until it's gone.
That was one reason Dennison wanted to grade the state's major rivers - so Marylanders would know about the failures before it was too late to fix them.
Federal and state environmental officials were initially reluctant. Even now, natural resources officials say Dennison's report is merely a weather-dependent snapshot in time.
State officials say they have to balance the river's needs with those of watermen and farmers who have to make a living and residents who want to live on the Shore.
"It took us a long time to pollute these rivers, and it's going to take a long time to clean them up," said Bruce Michael, director of the state's tidewater ecosystem assessment division. "We're doing it, to some degree, but we have to do more."
Dennison is losing patience with such pronouncements. He worries that the river might not only fail to improve in his lifetime but could die on his watch.
"The Choptank is teetering on the brink," he said. "We need to fix it now."