The U.S. Army Corps of Engineers and the National Park Service insert post and panels to test the 17th Street closure, Washington, D.C., Oct. 31, 2014. The 17th Street closure is a removable structure that can be erected in the event of high water from the Potomac River to attach to the floodwalls on both sides of 17th Street and consists of aluminum panels between steel posts. The closure is part of the Potomac Park Levee System and the Washington, D.C. and Vicinity Local Flood Protection Project. (U.S. Army Photo by Brittany Bangert/Released) The closure structure, situated between the Lincoln Memorial and the Washington Monument, is regulated by the Corps and will be operated and maintained by the National Park Service.