Des Moines Rapids
Coordinates: 40°28′10″N 91°22′15″W / 40.469543°N 91.3707°W
The Des Moines Rapids between Nauvoo, Illinois and Keokuk, Iowa-Hamilton, Illinois is one of two major rapids on the Mississippi River that limited Steamboat traffic on the river through the early 19th century.
The rapids just above the confluence of the Des Moines River were to contribute to the Honey War in the 1830s between Missouri and Iowa over the Sullivan Line that separates the two states.
Various attempts to make the river navigable started in 1837 when a channel was blasted through the rapids by U.S. Army Corps of Engineers team led by Robert E. Lee. A canal around the rapids was built in 1877. It is now obliterated by Lock and Dam No. 19.
The other major rapids barring traffic on the Mississippi is the Rock Island Rapids.
The Mississippi in its natural state widens from 2,500 feet (760 m) to 4,500 feet (1,400 m) in width at Nauvoo as it drops 22 feet (6.7 m) over 11 miles (18 km) over shallow limestone rocks to the confluence with Des Moines.
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Wikipedia