The bridge over the spillway was replaced in 1975 and again in 2005 . In that same year , because of the September 11 attacks on New York City , the New York City Department of Environmental Protection proposed permanent closure of the road across the top of the dam . Pedestrians and emergency vehicles were allowed to use New Croton Dam Road , but all other traffic was re-routed . The department made plans to replace temporary vehicle barriers with permanent barriers after completion of a New Croton Dam Rehabilitation Project in 2011
September 11 attacks
September 11 attacks
New Croton Dam