Black Lagoon: Sudbury Reservoir tributary tainted

PHOTO GALLERY: The Black Lagoon is a contaminated man-made pond near the corner of Maple and Walker streets in Marlborough, Mass. For more than a century, petroleum-product spills have plagued properties on a mile-long stretch of Maple Street. Toxins from those spills now rest uneasily in The Black Lagoon, mingled in massive silt deposits that pose a threat to the nearby Sudbury Reservoir. Read MetroWest Daily News Special Report

MOTHER OF THE BLACK LAGOON: A state Department of Conservation and Recreation-owned pond along Maple and Framingham streets in Marlborough is filled with garbage and oil-tainted silt. This squalid swamp feeds another contaminated DCR pond about 1,000 feet downstream off Walker Street. /Allan Jung photo for MetroWest Daily News

PETROLEUM POLLUTION: An oily sheen floats on top of water in a drainage ditch at a culvert across from 299 Maple St. This ditch drains into a 6-foot-wide concrete aqueduct that flows to the DCR-owned pond off Walker Street. /Allan Jung photo for MetroWest Daily News

DOUBLE THREAT: Two DCR-owned ponds in the Maple Street neighborhood of Marlborough are filled with oil-tainted silt. The Sudbury Reservoir is about a quarter-mile downstream of The Black Lagoon, which is contained behind an aging concrete-and-earthen dam off Walker Street. /Google Earth image and bullworkofdemocracy illustration

NEIGHBORHOOD BLIGHT: Homeowners who live next to The Black Lagoon, including Dionysi McGowan of Walker Street, are calling for DCR to cleanup the pond. About three years ago, McGowan says he saw an alarming oil slick in the pond. "It was every color of the rainbow," he said. /Allan Jung photo for MetroWest Daily News

OIL SPILL LEGACY: An oily substance bleeds from a silt deposit in the center of The Black Lagoon. Most of the volume of the football-field-sized pond is filled with silt. /Christopher Cheney photo

SPILLWAY SPILL: Oil sludge oozes from The Black Lagoon dam's floodgate spillway into the dry floor of the main spillway. /Allan Jung photo for MetroWest Daily News

CONTAMINATION CONDUIT: A quarter-mile-long concrete aqueduct connects The Black Lagoon dam's main spillway to the Sudbury Reservoir. The terminus point of the main-spillway aqueduct pours into the reservoir in Southborough, Mass. /Christopher Cheney photos

TAINTED TERMINUS: The Black Lagoon dam's main-spillway aqueduct, left, and floodgate-spillway drainage stream converge at an inlet to the Sudbury Reservoir that is dotted with silt deposits. /Christopher Cheney photo

PROBLEMATIC PIPE: An oily sheen floats on water at an outflow pipe in the concrete aqueduct connecting The Black Lagoon to the Sudbury Reservoir, which is about 1,000 feet downstream. /Christopher Cheney photo 

POLLUTED RESOURCE: Garbage and other debris float in the Sudbury Reservoir. /Allan Jung photo for MetroWest Daily News

GOING WITH THE FLOW: For decades, tainted silt has been flowing into the Sudbury Reservoir from The Black Lagoon. /Google Earth image and bullworkofdemocracy illustration