St. Mary's River still on sick list

Moratorium on oystering suggested

Wednesday, Nov. 18, 2009

The river bottom has no dissolved oxygen in the summer, plant growth is down, the oyster harvest is minimal, and the overall health of the river has steadily been declining, the St. Mary's County commissioners were told Tuesday.

"I wish I had better news to report," said Joseph F. Anderson, president of the St. Mary's River Watershed Association, but the river has been in a "steady state of decline for some time."

The association and St. Mary's College of Maryland have been tracking water quality since 1999. "Every summer there's no oxygen in the bottom of the St. Mary's River," said Robert Paul, director of the river project, and biology professor at the college.

The lack of oxygen kills organisms. "What's driving this? Primarily algae and nutrients coming into the water" via runoff, Paul he said. "Every June it starts and continues through the summer. The warmer it gets, the less oxygen it can hold," he said. No oxygen — no oysters to filter out pollutants.

Water quality is going down, too, the commissioners were told. When the sunlight can't penetrate the water, aquatic plants die. Losing the plants means losing molting grounds for juvenile crabs.

In 1974, 90,000 bushels of oysters were pulled from the river. Since 2000, the annual harvest has been about 1,500 bushels and "it's not going up," said Bob Lewis, executive director of the watershed association.

In dry summers, water clarity increases and aquatic plants grow because nutrients aren't being carried off from the land to feed algae. In wet weather algae blooms flare up, fed by the nutrients that run off from the land. The algae then dies, sinking to the bottom where bacteria eat up available oxygen as they break down the algae.

Much of the St. Mary's River watershed is in the Lexington Park Development District, an area of intended growth and with that comes more impervious surfaces that carry runoff and sediment into the river's feeding streams.

Last week, a nor'easter dropped between 5 and 7 inches of rain in two days. "That storm event created huge sediment loads being carried," Paul said.

The watershed association supports the development district, but advises preserving areas outside of its boundaries to soak up rainfall.

"All politics is local … and we have a watershed right in our control," Anderson said.

Commissioner Daniel H. Raley (D) asked if new stormwater regulations recently implemented by the state are the answer to improve water quality.

"No, it's not the answer, but it's a huge step in the right direction," Anderson said. "It's a big huge science project and we're learning as we go along. The difficulty is going to be enforcing these regulations."

Commissioner Larry Jarboe (R) said, "We look to the oyster as the ultimate savior" and asked if a five-year moratorium would work in the St. Mary's River.

"We think that's a great idea and we support that," Paul said, but there is still pressure from watermen trying to harvest oysters.

"We talk about harvest pressure, but we really got to get real," said Commission President Francis Jack Russell (D), who takes students on trips on the St. Mary's River through the Chesapeake Bay Field Lab. "I've seen three tongers in St. George's Creek," he said.

Russell said of a moratorium, "I think it's trying to attack the problem from the wrong end." Pollutants from farther up the Potomac River need to be addressed, he said, such as Blue Plains Advanced Wastewater Treatment Plant, a 150-acre site that treats Washington, D.C., sewage.

"They don't take ownership of what they're creating," said Commissioner Thomas A. Mattingly Sr. (D) of pollution from metropolitan areas farther upriver.

The river is 8 miles long from its mouth to the head of tide, with 84 miles of shoreline.

jbabcock@somdnews.com