A sheen on the surface of the Potomac River spotted Sunday, Nov. 27—later identified as lubricating oil leaked from the NRG Dickerson Power Generating Station in Montgomery County, MD—caused the Town of Leesburg Utilities Department to temporarily shut down its water intake in the river.
The oil slick, first spotted near Point of Rocks upstream of the town’s water intake, flowed directly over the town’s offshore submerged intake. The town filled its reserves to capacity on Monday in anticipation and shut down the intake as the slick approached. By Wednesday morning, the oil had drifted away and pumping had resumed.
“Our staff were among the first to identify the sheen,” said Leesburg public information officer Betsy Arnett. On Sunday, she said, the town’s utilities staff walked the banks of the Potomac to see the extent of the oil.
The town has since deployed a boom to divert contaminants away from the town’s intake, which remains in place, although Arnett said the sheen has drifted across the river away from the town and has not returned.
The Utilities Department continues to conduct additional testing and monitoring as a precaution.
Loudoun Water sources its water from Goose Greek and from Fairfax Water, which pumps from the Potomac River. Fairfax Water is also taking precautions, and both the Town of Leesburg and Fairfax Water said there was no need for customers to take any action.
The sheen, which was identified as less than 150 gallons of oil, has largely dissipated, according to the EPA. The EPA continues to investigate other evidence of sheen, reporting that it appears that degraded sheen from the original discharge lodged in “small discreet spots south of the plant” and was released “due to changing weather and shoreline conditions.”