Rock Run culvert (#12), on short level, just below Lock 11 (above Lock 10). NPS says: Built on an angle (under the berm, canal, and towpath) approximately 152' in length. The 12' -6" wide barrel arch, with rise of 5' -6", is horizontal. The side walls of the culvert taper from 8' high and the outflow to 5' at the inflow. The outlet (riverside) wall is of gray sandstone and the inlet (berm side) wall of red sandstone. The outlet wall runs for an extensive distance, due to the flood plain of Rock Run and is buttressed.