Paw Paw Slope Stabilization

Originally constructed from 1828-1850, the Chesapeake & Ohio (C&O) Canal was one of the first largescale civil works projects funded by the U.S. Government, with supplemental funds from Mary- land and Virginia. The canal's navi- gational system stretched along the Potomac River for 184.5 mi (296 km) from Washington, D.C., to Cumberland, Maryland. The C&O Canal's navigational system was primarily comprised of locally sourced materials such as stone, earth, timber, mortar and brick. The Paw Paw Tunnel was con- structed by the C&O Canal Company in lieu of building 6.7 mi (11 km) of canal along the Potomac River (referred to as the Paw Paw Bends). The tunnel is approximately 3,118 ft (950 m) long, 25 ft (8m) wide, lined with six million bricks, and included open cuts through the interbedded shale and siltstone on both sides of the approaches to the tunnel en- trances. The excavation passed through the Tunnel Hill Ridge and the Valley of Mill Run (a stream that still conveys water through the cut in the form of waterfalls). After the full section of canal through the project area was opened in 1850, it remained in commercial oper- ation for 74 years until 1924. Today, the Paw Paw Slope Stabiliza- tion Project is located in one of the most remote portions of the Chesapeake & Ohio Canal National Historical Park, approximately 155 river miles (250 km) upstream of Washington, D.C., and under the management of the National Park Service. There is a rich history of rock fall and slope instability within the cut on the downstream approach to the tunnel. This is due to a combination of