Michael Grahek trudged through the murk of a historic Los Angeles Department of Water and Power water tunnel, his flashlight sweeping its century-old concrete walls. His light then settled on some a strange outlines in the Sylmar shaft. “Notice the footprints,” said Grahek, LADWP manager of southern aqueduct and Owens Lake Operations and maintenance, pausing inside the arched tunnel. “Somebody stepped in the wet cement almost 100 years ago.”