MUSCATINE, Iowa–When walking by the river or crossing the Norbert F. Beckey Bridge, one can hardly help but notice Lock and Dam 16, just outside Muscatine. However, few people know much about how the lock and dam works and how the imposing 85-year-old structure came to grace the Mississippi River. For their final program of the year, the Rotary Club of Muscatine invited Cindy Klebe from the U.S. Army Corps of Engineers to come share a little about what makes Lock and Dam 16 a valuable part of the lock and dam system that makes the Mississippi River more navigable.
Though the United States government had tried to create a more navigable channel for the Upper Mississippi River several times, they did not fully succeed until the 1930s, when they created a system of 37 locks and dams from Minneapolis and Saint Paul in Minnesota all the way down to Saint Louis in Missouri.
From 1933 to 1937, the US Army Corps of Engineers built Lock and Dam 16, downstream from Lock and Dam 15 in Davenport, the first one they constructed. An example of transitions in lock and dam construction, Lock and Dam 16 represents the last one to use both non-submersible roller gates and Tainter gates of any kind with steel on only one side but the first to use line shafts rather than locomotive hoist cars to raise and lower the gates.
Efficiently constructed, Lock and Dam 16 can fill or empty to let a barge train through in about seven minutes. First, the lock and dam fills with water pulled in through intake tunnels on each side with portholes to allow the water to flow into the lock. Once filled, up to nine barges may enter the lock. Large barge trains may need to disconnect and come through as two separate groups. Then, the water drains out of upstream discharge outlets, bringing the barges down to the lower level of the downstream channel. Lock and dam operators may then bring in and let out a little water to create enough movement in the water to push the barges out. The can then repeat the process for any remaining barges. Built at a time of very low water, all of the locks and dams on the upper Mississippi River remain navigable even in droughts.
Each year, tons of products travel up and down the Mississippi River, with grain and other agricultural projects predominantly traveling down the river and components of concrete traveling up the river. This method of transportation represents one of the most efficient, with one tow boat with 15 barges carrying as much cargo as 240 train cars or 1,050 semi trucks. This naturally reduces the amount of truck traffic on highways, making them less congested for travelers using them.
About every 25 years, locks and dams undergo a dewatering, where the US Army Corps of Engineers drains them in the winter and repairs parts they cannot access underwater, such a concrete sections that may need repouring, valves, piping, air bubblers, and anchorage points. Recently Lock and Dam 15 underwent this process, though Klebe did not state when Lock and Dam 16 would need its next dewatering. In the future, if infrastructure funding permits, Lock and Dam 16 could undergo renovation to allow 15 barge trains to go through without disconnecting, as they do at some of the larger locks and dams elsewhere on the river.
