On Feb. 24, Peggy Weidlein was driving into Normanstone Park when something “very, very green” caught her eye, she says. The stream through the park was an intense, fluorescent green—emerging from a culvert under a roadway and flowing down into Rock Creek Park. “It was glowing,” Weidlein says. The substance resembled antifreeze, Weidlein says, but was odorless. Jerusalem Bekele, a program manager for the Water Quality Division of the D.C Department of Health, says the brightly colored water was the result of a dye test of sewer lines. “Once in a while, the pipe would have an output to a stream,” Bekele says. “It was draining the way we expected it to.” The stream itself, Weidlein says, seems to have survived. “The day after, my daughter saw a duck swimming in the same water,” she says. “It was almost the same as it had always been, but there was still a little bit of green in it.” —Bidisha Banerjee