Lock and Dam 25 is equipped the 1,296-foot long dam structure with three submersible roller gates (near the center of the structure, see image at right) and 14 submersible tainter gates. At the time of construction, the submersible gates represented a marked advance in gate design and were seen as an improvement over non-submersible gates because they allowed for the almost unobstructed flow of floodwaters, ice and debris.