WASHINGTON — Water officials are keeping an eye out and making preparations as an unidentified sheen on the surface of the Potomac River slowly makes its way toward some of the area’s drinking-water intakes.
“It’s not like a huge oil slick, but it’s got the prismatic colors indicative of an oil slick,” said Tom Jacobus, general manager of the Washington Aqueduct. Operated by the U.S. Army Corps of Engineers, the aqueduct processes drinking water for the District, Arlington County and the City of Falls Church.
Jacobus said rain expected Wednesday will help move and dissipate the product, which appears to be similar to a hydraulic fluid or lubricant. Aqueduct officials have closed their Great Falls intake.
“Customers won’t notice a thing in the quality and quantity of their drinking water,” Jacobus said.
The slick was observed Monday from a U.S. Park Police helicopter, Jacobus said, adding, “We’re going to put another copter up today. The river is low, and the pollutant is flowing slowly.”
The Washington Suburban Sanitary Commission said in a statement Tuesday evening the sheen is still several miles north of an intake at its Potomac River filtration plant. Initially, WSSC anticipated the sheen would reach its plant Tuesday morning.
The plant produces about 70 percent of WSSC’s treated water for Montgomery and Prince George’s counties, the commission said.
The plume is expected to reach Great Falls several hours after passing the WSSC plant, which is located upriver, in northwestern Montgomery County.
“Out of an abundance of caution we’ve already put a boom up in front of Great Falls, which is one of our two intakes,” Jacobus said. “The other is at Little Falls.”
WSSC said that they’ve filled their system to capacity, closed the intake late Monday night and would reopen it after the plume passes. They’re also doing additional testing on the water that’s coming into the plant before it goes out to customers, and they have put a boom in the river to divert water.
The plume was discovered Sunday near Point of Rocks, Maryland.
Fairfax Water, Frederick County, the Town of Leesburg, and the City of Rockville are also keeping watch on the sheen, the Metropolitan Washington Council of Governments said in a statement.