What is a navigation lock? 

A navigation lock is a structure used to raise and lower vessels between two bodies of water at different levels on a river or canal waterway.  Locks make navigating a river easier by allowing vessels to take advantage of deeper water levels provided by dams.  The first recorded lock chamber dates back to 983 AD. 

The general design of those ancient locks varies from today’s modern structures only in technology.  The major components of a lock are essentially unchanged.  Every lock has strong parallel walls on each side to hold the water; gates on each end of the walls to allow vessels in and out, as well as isolate the chamber area from the water levels outside the lock; and some device to allow water to flow into and out of the chamber.  Most locks generally operate the same way: 

• The entrance gates are opened and the boat moves in.
• The entrance gates are closed.
• A valve is opened, water in the chamber is lowered (downstream) or raised (upstream) to meet the level of the water outside the chamber.
• The exit gates are opened and the boat moves out.

The Nashville District operates and maintains fourteen projects with navigation locks.  Ten of these locks are considered “high lift” locks because they raise vessels over 55 feet from the river below the lock to lake above them.  Wilson Lock in Florence, Alabama is the highest single lift lock east of the Rocky Mountains.  A vessel locking through Wilson Lock is lifted 94 feet from the river below to the lake above the dam.

From 1888 until 1928 the U.S. Army Corps of Engineers struggled against all odds to create a system of locks and dams along the Cumberland River to aid navigation and facilitate trade. The concept for these navigational aids began in the mid-19th century, but construction would not begin for nearly 50 years.

A perpetual shortage of money plagued this project from its inception until its completion. The Chief of Engineers was always asking for enough money to complete the project, and was always given a fraction of the sum requested, if any appropriations were forthcoming at all. But the engineers persisted and push ahead.

These locks and dams were cons tructed using the technology of the 19th century. Stone was quarried, cut and laid by hand. The cribs for the dams were frames built of wood, which were submerged and filled with rocks. This work was done by hand. Workers swam underwater to make repairs and feel the bottom to insure that the cribs were properly placed. Men packed down clay in the construction process with their bare feet.

Yes, there were steam dredges, trams and derricks, but these were not too far removed from the machines used by Civil War engineers. Though steam power existed, man and animal power provided the lion’s share of the power that made these locks and dams a reality. Modern innovations were utilized in the process of constructing the locks and dams. Concrete was used for some of the locks and one of the dams, but for the most part the project was built the way locks and dams had been built for centuries.

Over the 40 years it took to construct the fifteen locks and dams of the Cumberland Improvement Project the world changed greatly. The Annual Reports for the last few locks and dams mention connecting electricity and telephone lines to the locks and lock facilities.

Automobiles and trucks were becoming commonplace, the good roads movement was underway, and this new form of transportation would soon eclipse the locomotive. Even though this system of locks and dams was almost obsolete as soon as it was completed these locks were, and are, an important part of the history of the Cumberland River, Kentucky, Tennessee and the United States.