Development Cited in River Damage
By David A. Fahrenthold
The Severn River has been heavily damaged by development along its banks, which has resulted in low-oxygen "dead zones" and caused the decline of one of the river's best-loved fish species, according to a new report from the Severn Riverkeeper Program.
The nonprofit environmental group's report, released last week, found that water along the river bottom routinely had too little dissolved oxygen because of pollution-driven blooms of algae. During much of the summer, the report said, some sections of the Severn could be labeled dead zones, unfit for many of the river's creatures.
The source of the problem is not an oil spill or industrial mega-polluter, the Riverkeeper program found, but rather the homes and streets that line the Severn and its tributaries. The most damaging pollutants, the report said, are washing off streets and yards, or leaking from underground septic tanks.
"We found that the Severn is a dying river," said riverkeeper Fred Kelly, a leader at the program.
The Severn stretches about 11 miles from Severn Run, near Interstate 97, to its mouth downstream of Annapolis. The river is not nearly as polluted as some Chesapeake Bay tributaries farther north: The Back River is burdened by a nearby sewage treatment plant, and the Patapsco River is affected by the industrial contamination of Baltimore Harbor.
But the Severn has serious problems. At least 17 percent of its watershed is covered by man-made surfaces, Maryland scientists say. That's much higher than the ratio for the entire Chesapeake watershed, which was about 1.76 percent at last tally, according to the Environmental Protection Agency's Chesapeake Bay Program.
Scientists who study the river say that these paved areas deprive the river of the natural filters provided by earth and vegetation. Instead of trickling slowly down, and being purified along the way, rainwater runs off roads, roofs and parking lots at high speed, carrying such things as motor oil, fertilizer and dirt.
In the water, all of these spell trouble. Fertilizers can feed the algae blooms that suck oxygen out of water. And even dirt can be harmful: It clouds the water, preventing sunlight from reaching underwater grasses. Dirt also can bury life on the river bottom, such as eggs laid by the Severn's once-famous stock of yellow perch.
"If you looked in the water, you would see dead oysters," Kelly said. "You would not see all the small yellow perch. . . . You wouldn't see the fish, and you wouldn't see the crabs."
"That's what happens" in a river as troubled as the Severn, he said.
In the 1950s, according to state estimates, 60 to 98 percent of the yellow perch eggs were capable of hatching. But that has fallen to about 10 percent, according to recent research.
"It's a poster child for the effects of development and urbanization in a tidal watershed," said Jim Uphoff, a scientist with the Maryland Department of Natural Resources. He and his colleagues cite the Severn's problems when they make presentations in less-developed areas, warning about what will happen if too many roads and neighborhoods are built.
But Kelly, the Severn riverkeeper, said some of the problems could be solved if the state used money from its new Chesapeake Bay 2010 Trust Fund to finance projects that would clean storm water flowing into the river.
He said he hopes to replicate the success at Howard's Branch, where storm water from the neighborhoods of Sherwood Forest and the Downs is now funneled through man-made pools.
Kelly said he also wants the state and Anne Arundel County to help homeowners living near the river's edge to test their septic systems to determine if too much pollution is leaking from their tanks.
"We don't need any more studies," Kelly said. "We know the solutions."
(Revised Feb 2008)