The Mississippi's southernmost major tributary, the Arkansas, is born from melting snow on the eastern slopes of the Continental Divide near Leadville, Colorado. Its 1,450-mile course drains 160,500 square miles in five states.
Despite dramatic seasonal changes in depth, the Arkansas was a busy river in the 1800's with keelboats and later steamboats running much of its length Frequent floods, however, caused serious navigation problems and made the Arkansas basin a precarious place to live. Today, seventeen dams of the Arkansas River Navigation System control streamflow and depth. A 439-mile navigable waterway carries year-round barge traffic from northwest Oklahoma to the Mississippi River.
The Navigation System waterway abandons the Arkansas channel north of its mouth, taking a short-cut east through a bayou to reach the Mississippi on the White River, 13 river miles north of Arkansas's mouth. The White remains navigable 300 miles upriver to Batesville, Arkansas. Its headwaters lie 700 miles from its mouth in the Ozarks of North-west Arkansas.