Erie Canal Lock 8 was built as part of New York State's expanded Barge Canal, whose larger locks replaced the original Erie Canal locks that measured 90 feet long and 15 feet wide and fit canal boats around 60 feet long and seven feet wide. The new locks measured more than 320 feet long and 45 feet wide with a depth of 12 feet of water to accommodate boats up to 300 feet long. Along the Mohawk River, Locks E8 through E15 featured a dam based on a design found on the Moldau, the Czech Republic's longest river. At Lock 8, construction of the three-span movable dam began in 1908. At 510 feet wide, it can raise and lower boats by as much as 15 feet when activated. Although often mistaken for a bridge, its walkway is used only for maintenance. Beneath the dam's trusses, steel frames hold giant steel plates, and below the surface a concrete sill stretches across the full width of the river floor; when the frames are swung open and lowered by chains to sit on the sill, they form a dam.
