Stream remediation creates environmental debate

November 18, 2014

Many communities in Baltimore County have come under pressure from regulators to reduce the level of pollution finding its way to the Chesapeake Bay. The bay is currently the subject of a $450 million revitalization effort to reduce pollution, promote tourism and encourage economic growth in the area. 

Part of the restoration effort includes addressing the pollution levels of streams and tributaries that flow into the bay. Nearly 3,700 miles of streams across Maryland are targeted for remediation work by 2025, nearly all of them in urban areas, according to a panel of experts referenced by the Baltimore Sun. 

Stream bank erosion is believed to be a major source of sediment pollution in the bay and its tributaries, and also is thought to contribute to the bay's algae blooms. Phosphorous, which is known to contribute to algae growth, "clings" to particles in the soil. 

One of the strategies for reducing erosion is the installation of stones along the sides and bottom of river channels. Other streams are being redirected to create more bends and curves to help trap some of the sediment and prevent pollution from finding its way into the bay. 

However, some scientists and environmental researchers are questioning the efficacy of these remediation strategies. 

"You can't ask a stream to do everything an entire watershed should do," Margaret A. Palmer, a University of Maryland scientist who specialized in restoration ecology told The Baltimore Sun. "Show me that the water quality is better after restoration than before. In the vast majority of cases, the data do not exist."

Those in favor of restorations commonly point to Minebank Run, a restored county stream, which has shown reductions in sediment and nutrients as a result of these remediation strategies mentioned above. But for other remediated streams, the benefits are not as clear. 

The Environmental Protection Agency currently accepts these methods of stream restoration, and considers them effective in reducing sediment pollution.

"I think restoration science is still at a pretty early stage, and we have an obligation to learn as much as we can from it and recognize we don't have all the answers," Erik Michelsen, manager of stormwater control efforts for Anne Arundel County, told the source. 

With such a widespread and controversial effort, it is crucial that experienced environmental consultants are retained in order to provide the necessary insight for strategy design. These consultant can help officials determine the most cost-effective manner of approaching stream remediation.