The first structure at this location was built from 1921 to 1924 as part of the 6-foot navigation channel project. It consisted of a canal that bypassed a particularly hazardous section of rapids. It included a lock to control water flow through the canal. That canal is on the Iowa side of the river.
Starting in 1935, the modern lock and dam structure was built. A new lock was added on the east side of an island near the Iowa shore. A 1,343 foot long control structure was built consisting of 13 Tainter gates and 4 roller gates, along with a 1,127 foot long earth embankment to connect to the Illinois side. This allowed the entire river level to be raised high enough to submerge the rapids below the 9-foot deep navigation channel. A second lock and dam just down river in Davenport raised the river level high enough to submerge the rest of the rapids.
The original lock was rebuilt, and is now an auxiliary lock used for pleasure craft during periods of high travel demands. The lock itself is 80 feet wide by 320 feet long, so it is far too small to be of use for barge traffic. Interestingly enough, to reach the viewing area for Lock & Dam #14, you have to cross the auxiliary lock on foot. That crossing is a pedestrian bridge built on top of the lower lock exit doors. There is a light bridge for auto traffic that also crosses the lock, which limits the height of boats that are able to use the auxiliary lock.
The various local government agencies along with some local clubs have really gone to work to create recreational activities around the lock and dam structure. The Illinois side features Fisherman's Park, which has both a day use area as well as a modern campground. The Iowa side has a large park on the island in the middle of the river, a boat landing below the dam, a Nature Conservancy area, and Smith's Island. The Hoepfner family farmed Smith Island in the river in the late 1800s and early 1900s. When the dam was built, it submerged much of their farm. Smith's Island was off limits for many years. Recently, the US Army Corps of Engineers built a pedestrian bridge to the island, and developed a series of trails. One may now venture out onto the island to locate the remains of the Hoepfner family homestead.