The park has an ongoing construction project in the Big Slackwater area that involves the reconstruction of the towpath along the Potomac River. This two-mile section of towpath was destroyed by a storm in 1996, resulting in it being closed to visitor use since that date, and last year received ARRA funds for its reconstruction. On the evening of April 14th, two bicyclists, a father and his 15-year-old son, were on their return trip upstream on the towpath and decided it was safer to enter the closed section than to take the designated detour on the rural roads. They trespassed through three closed signs and a barricade to enter this area. While walking their bikes on this precarious route, the father slipped and fell into the river. He then swam out to a construction barge, where he became stranded while his son was stranded on the edge of the shore. He called 911 on his cell phone to be rescued. Rangers and local fire and rescue personnel responded to the incident. The two were rescued by boat and the father received an educational charge to obey closure signs.