A recent surge of aquatic vegetation and reprieve from damaging runoff have resulted in the cleanest water in decades in the Susquehanna Flats area of the Chesapeake.

Grasses' revival a bright spot for bay

September 15, 2005|By Candus Thomson | Candus Thomson,SUN STAFF

HAVRE DE GRACE -- Just five months ago, the water coursing over the Conowingo Dam and into the confluence of the Susquehanna River and Chesapeake Bay was a chocolate brown slick of muck visible from outer space.

Today, the water is gin clear, a picture window on the creatures below.

Baby striped bass dart from grass clump to grass clump as catfish the size of a man's forearm cruise by. Largemouth bass lurk at the edge of an underwater hedge of green, waiting for dinner to swim along. A wader can reach the bottom and grab a fistful of freshwater clams.

"It's as good as it can get," says Capt. Mike Benjamin, a fishing guide on the upper Chesapeake. "On a scale of 1 to 10, it's a 20 when compared to 20 years ago."

For the second year in a row, the aquatic vegetation in the area known as Susquehanna Flats is like a Kansas cornfield in midsummer. A six-week dry spell has given the bay grasses a reprieve from damaging runoff, allowing thick islands of plants to cover more than 10,000 acres -- about three times the size of Baltimore-Washington International Airport.

But unlike last year, this year's crop has ushered in a level of water clarity not seen in decades. The plants are slowing the flow of river water and straining sediment.

"They're acting just like a big aquarium filter," says Benjamin.

At a time when oxygen-starved dead zones in the Chesapeake are the talk of environmentalists and fishermen, the discovery of clean water teeming with life is a small but welcome sign.

"What we're seeing is a peek at what the bay could look like if all of our [cleanup] strategies were adopted," says Mike Naylor, a biologist with the state Department of Natural Resources.

Susquehanna Flats is Maryland's welcome mat to the Chesapeake Bay. Topographically, it is an upside-down bowl in the bay nestled between Harford and Cecil counties, with depths ranging from a few inches to a few feet. Around the rim is a channel of deeper water.

"The Flats," as locals and fishermen call it, is in the middle of the East Coast's largest striped bass spawning ground. In spring, its surface is covered with fishing boats filled with anglers kicking off a new season. In late fall, hunters go "body booting," hunkering down in chest-high waders amid their decoys, waiting for ducks and geese to fly over.

But its location and shallowness also make the area easy pickings for harsh weather. The low point came in 1972, when floodwaters from Hurricane Agnes uprooted and killed as many as two-thirds of all the bay's grass beds.

Last summer, scientists announced a resurgence of grasses in this small portion of the upper bay, crediting a reduction in farm runoff in Pennsylvania and Maryland and fewer spills from sewage treatment plants. But weeks later, the remnants of Hurricane Ivan dumped up to a half-foot of rain on the Susquehanna watershed, forcing the operators of the Conowingo Dam to open 33 of its 50 floodgates. Debris scoured the grass beds, and floodwaters dumped up to a foot of silt where the plants had been.

"I thought it was all gone," says Benjamin. "No grass beds, no fish, no ducks. It was depressing."

This spring, it was more of the same, when heavy rains churned up enough sediment and debris to leave a dark brown streak from Harrisburg, Pa., to just below Kent Island that was visible on satellite imagery.

But the weather settled down, as did the runoff that fueled the growth of sunlight-blocking algae. The grasses surged, giving scientists hope that the upper bay is within striking distance of the recorded high of 13,000 acres reached in 1952.

"When we don't get runoff, the bay shows its resilience. The grasses stabilize the bottom and you put the system back in balance," says Bill Goldsborough, senior scientist for the Chesapeake Bay Foundation.

But getting back to 1950s levels won't be easy, Naylor cautions. Extreme weather, poor land use and failure of sewage treatment plants hinder growth. Some dock owners complain that the vegetation fouls boat propellers and want DNR's permission to apply weed killer.

"The beds aren't going to keep spreading out on their own," Naylor says. "If we can increase water clarity by just a few inches, we can increase the beds by hundreds of acres."

The Department of Natural Resources continues its outreach through its Web site www.eyesonthebay.net, but as he stands on a small boat, looking down at the clear water, Naylor offers another strategy.

"If all the people who enjoy being in and on the bay could see this," he says, "they would demand that the rest of the bay look like this."

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