These two rivers have played a vital part in development of their basins. First explorers, then traders and settlers used the rivers as water highways. The settlement of the town of Mobile was successful largely because of its ideal location to serve as a port of the inland river system.
  In the nineteenth century, cultivation of cotton and invention of the paddlewheel steamboat stimulated trade on the rivers. But hazards such as sandbars, fallen trees and shoals impeded navigation. In 1875, the first plans to improve the rivers for navigation were approved.
  Between 1895 and 1915, a system of 17 locks and dams was constructed between Mobile and Birmingham. In those days, waterway construction was a slow and laborious task. Dams were built by hand of stone and mortar. Locks were walled with stone-filled timber cribs, and hauling was done by mule-power.
  The original locks and dams were built to provide a six-foot-deep channel, adequate for the steam-powered tow boats and packets of the era. The Corps undertook a program to modernize the system in 1937. The 17 low-lift locks (Old Lock #2 was one of these) were replaced by six high-lift locks, capable of expediting present-day towboats and barges.
  All of the original locks and dams have been replaced except for John Hollis Bankhead Dam on the Black Warrior near Birmingham. The structures at Bankhead were the last of the original locks and dams built on the system.

  This information was gathered from the U.S. Army Corps of Engineers website.