The Clarence Street Bridge (also known as Bridge 21) is a vertical-lift bridge located in Port Colborne, Ontario. Built in 1929 during 4th Welland Canal Construction, the bridge still serves today as a vital link connecting East and West Port Colborne. The structure uses simple electric motors and counterweights to raise the deck 36.5 meters (120ft.) above passing vessels. The raising and lowering of the bridge takes approximately 90 seconds. The western bridge approach, over former canal locks 26 and 27, was added when Bridge 21 was constructed, making these locks inoperable.