The main dam structure is 1,066 feet long, and features 10 Tainter gates and 3 wider roller gates. The Illinois side consists of a 8,940 foot earth embankment, while the Iowa side has a 4,073 foot earth embankment which includes a 1,650 foot secondary spillway. The locks are typical of the Mississippi River locks being 110 feet wide by 600 feet long. Many of the Mississippi River locks have a second uncompleted auxiliary lock, as does Lock & Dam #13. The auxiliary lock has the upper entrance doors installed and working, but no lower exit doors. The auxiliary lock could be opened if the main lock were to fail.