The Chesapeake Bay Foundation is pointing to a report that adds 37 streams and waterways to the state’s most-polluted list as evidence of the need to curb runoff in urban and suburban areas.
For 15 of the streams newly listed — either because of high pollution levels or the detection of an additional pollutant — urban runoff and storm sewers were named as the source in the Maryland Department of the Environment’s draft report to the U.S. Environmental Protection Agency.
Roads, roofs, parking lots, patios, sidewalks and other impervious surfaces make up a higher percentage of the landscape in more heavily developed areas. These surfaces decrease the opportunities for rain and other deposits to soak into the ground, where they may be filtered or absorbed by vegetation.
According to MDE, among Maryland waters most polluted by runoff from urban or suburban areas were streams linked to the Potomac River in Montgomery, Frederick and Washington counties; the Anacostia River in Prince George’s and Montgomery counties; the Little Patuxent River in Anne Arundel and Howard counties; Liberty Reservoir watershed in Carroll and Baltimore counties; Back River in Baltimore city and Baltimore County; Lower Gunpowder Falls in Baltimore County; West River in Anne Arundel County and the Deep Creek Lake watershed in Garrett County.
Chlorides and sulfates were the added pollutants in the more-urban streams, and suspended solids were the added pollutants in less-urban waters that were added to the most-polluted list because of urban-type runoff.
But runoff from animal waste and septic tanks appears to be a cause of higher levels of fecal bacteria that put 14 waterways in rural areas of the state on the most-polluted list, among them six creeks where shellfish harvesting restrictions have been imposed: Broad, Edge and Lower Domingo Creek in Talbot County; Little Choptank and Jenkins in Dorchester County, and Daughery Creek in Somerset County.
More than two dozen waterways on the most-polluted list were marked as high priority in the state’s report, ranging across Maryland from the Lower Wicomico River and Sinepuxent and Chincoteague bays on the Eastern Shore, to the lower tidal Susquehanna River at the head of the Chesapeake Bay, to the Rocky Gorge Reservoir in central Maryland and the Youghiogheny River in western Maryland
Not all the news was bad, however.
MDE reported 11 waterways that had been deemed polluted now met federal water quality standards. Among them were the Miles River in Talbot County, which had been closed to shell-fishing, and Deep Creek Lake, a big recreational draw in Garrett County that had been listed for phosphorus pollution.
The report marks the first time Maryland has submitted the information in geographic information system format, which MDE says will help it report and assess pollutant levels as required by the federal Clean Water Act.
The fate of legislation aimed at helping cut some sources of the pollutants was uncertain as the Maryland General Assembly was drawing to an expected close Monday.