The oldest elements of Lock and Dam 14 were built between 1921 and 1924. Those portions were part of the 6-foot channel project and included a canal that let vessels bypass the notorious Rock Island Rapids. Construction on the rest of the lock, part of the 9-foot channel project, began in 1935. The dam consists of 13 Tainter gates and four roller gates. The main lock is on the Iowa side and can raise a vessel up to 11 feet.