The Chesapeake Bay is the largest estuary in North America. It’s fed by 100,000 creeks, streams and rivers.
It's home to more than 3,700 species of plants and animals, including crabs and oysters. And many say that it's in trouble.
Conservationists say that pollution from farms, wastewater treatment facilities, storm water runoff, and power plants in the 64,000 square mile watershed -- which includes parts of six states and the nation's capital -- is slowly killing the bay.
“What happens is too much pollution causes an explosion of algae,” said Will Baker, with the Chesapeake Bay Foundation. “When the algae die, they decompose and they use up oxygen in the water.”
“When you have no dissolved oxygen, you have dead zones,” said Baker. “Dead zones kill fish, kill oysters, kill crabs.”
Warm waters fuel the growth of these dead zones during the summer, threatening an important economic engine for the region.
“A dead Chesapeake Bay means much reduced tourism,” said Baker. “It means unhealthy seafood, unhealthy water to swim in. It means the lack of revenues from all the areas that the Bay generates.”
We rode out to take a closer look.
“We're going to head where the water's about 30 feet deep, and that's where I was seeing some really bad water the other day,” said John Rodenhausen, with the Chesapeake Bay Foundation
We measured oxygen levels in the water.
“Most critters like 5 parts per million or greater, so we're hoping for a number of 5.0 or greater,” said Rodenhausen. “We're getting down close to the bottom. This, in and of itself, is not a good reading, so odds are good that there are not a whole lot of fish on the bottom. “
So can anything survive down there?
“Not well, no,” said Rodenhausen.
In fact, the readings were poor all the way up to the surface. In an effort to improve the bay's condition, the Environmental Protection Agency set limits on the amount of nitrogen, phosphorous, and sediment allowed in the waters -- a so-called "pollution diet" that's been agreed to by the six states and the District of Columbia.
The goal is to cut pollution to these levels by 2025, with the hope to get more than halfway there by 2017.
The program has borne fruit, according to EPA administrator Lisa Jackson, who we spoke with along the Anacostia River in Washington -- one of the most polluted rivers running into the Chesapeake.
“The progress has been steady, but not fast enough. And I keep saying now is not the time to quit. We are so close to actually turning that corner, but it's going to require all of us: the federal government, state partners, local and county governments, municipalities, all alike to keep putting in our share,” aid Jackson.
Meeting the EPA’s goals will cost billions of dollars. And while some federal help is available, those funds won't cover the whole bill. Failure to meet the targets could result in fewer federal grants, tougher factory permit regulations, and stricter regulations for farmers, who the EPA says are the biggest contributors to bay pollution.
Opponents, like the American Farm Bureau, question the EPA’s data and say the plan will kill jobs. They've filed suit to block it.
“This approach from EPA is too heavy-handed, and it's going to cost people in this watershed significantly,” said Don Parrish with the American Farm Bureau.
Parrish said farmers have already cut back on fertilizers and have created buffer zones to reduce runoff.
“Farmers want that cleaner bay, but they also know from their standpoint, they are already on a razor's edge,” he said. ”And if you push this envelope, it could really have a significant impact on the ability for farms to operate.”