The Missouri River

The Missouri River is 2315 miles long, stretching 1755 miles from its Montana headwaters to Nebraska City and 560 miles farther to its mouth near St. Louis, Missouri, where it joins the Mississippi River. North America's longest river no longer resembles the waterway Lewis and Clark explored in the early 1800's, when regular floods in April and June, caused first by local ice and snow melt and then by snow melt in the Rocky Mountains, spread into low-lying areas, cut new channels, and created islands and sandbars by depositing nutrient-rich soil. The Lewis and Clark expedition spent 64 days traveling from Camp Wood, Illinois, to this point, along a river then made longer by its many curves. Beginning in 1927, the U.S. Army Corps of Engineers channeled the river from its confluence with the Mississippi to Sioux City, Iowa, creating a channel 200 feet wide and 6 feet deep for barge traffic. In 1944, the Pick-Sloan Plan called for five dams on the Missouri, and by the mid-1960's major floods on the river were largely over. Communities along the lower Missouri welcomed relief from annual flooding, but the river's controlled flow reduced the nutrient-rich sediment once deposited on low-lying ground during traditional flood seasons, the same process that had built the richness of bottomland farm fields over centuries. At this point, the land stands 190 feet above the river, with Iowa on the far shore and the Loess Hills visible in the distance.

Nebraska City, Nebraska · United States