Along the winding 2,500 mile course of the old Missouri, there existed a river reach unlike any other. Mountaineers, fur traders, and steamboat pilots knew that unique section of the river for its large number of snags, its deadly currents, and its frequent shifts in direction. That river reach extended from the mouth of the James River to the mouth of the Platte River.
Today it’s hard to imagine the Missouri as anything but a series of massive reservoirs in the Dakotas and Montana and a channelized ditch from Sioux City to the river’s mouth near St. Louis. But before the construction of the big dams across the upper valley and the navigation channel along the lower valley, the Missouri differed dramatically from place to place. For example, the Missouri that cut through the mountains near Helena, Montana, had little in common with the river that pushed sluggishly through the Dakotas; while the river that meandered through western Iowa looked and behaved nothing like the river that daily carried tons of prairie topsoil passed the Missouri state capital at Jefferson City.
The U.S. Army Corps of Engineers once delineated three distinct reaches along the Missouri. Those three reaches were: 1) the Muddy River (from the river’s mouth to the Platte); 2) the Sandy River, (from the Platte to the Yellowstone); and 3) the Rocky River, (the reach from the Yellowstone to the river’s headwaters at Three Forks). The name of each of these reaches reflected its predominant bed material.
Others knew the river as the Lower, Middle, and Upper Missouri. The Lower Missouri stretched from the mouth to Sioux City. The Middle Missouri extended from the mouth of the Big Sioux to the mouth of the Yellowstone. And the Upper Missouri stretched from the Yellowstone to the Three Forks.
Although the early delineation of the Missouri into three segments has merit, it’s more accurate to consider the Missouri as possessing six distinct reaches: 1) the Far Upper River (from Three Forks to the Gates of the Mountains); 2) the River of Falls and Rapids (from the Gates of the Mountains to Fort Benton); 3) the Rocky River (from Fort Benton to the Yellowstone); 4) the Plains River (extending from the Yellowstone to the James); 5) the Wild River (from the James to the Platte); and 6) the Big Muddy River (from the Platte to the mouth).
The river reach from the James to the Platte deserves to be known as the Wild River because it was along this reach that the Missouri experienced its greatest instability. The river through southeast South Dakota and western Iowa constantly shifted its direction, cut-off its long bends, abandoned old channels, scoured new channels across the valley floor, and formed oxbow lakes. The Wild River behaved like a writhing snake, perpetually slipping and sliding sideways from bluff line to bluff line. Valley residents never knew where the Wild River would strike next. There existed stories of valley farmers going to bed in their homes on the west bank of the Missouri in Nebraska, only to wake up the next morning to discover they lived on the river’s east bank in Iowa. Such was the fickle character of the wandering Missouri.
Why was the Missouri so unstable along the reach between the James and the Platte? More specifically, what was it about the environment of southeast South Dakota and western Iowa that created such an unpredictable stream?
Through Montana and the Dakotas the Missouri Valley is between one and three miles wide. That narrow valley hemmed in the river, preventing it from bouncing all over the place. The river could not cut long loops or dart great distances across the valley floor because shale and chalk bluffs blocked its path. But below the mouth of the James, the Missouri Valley widens out. In Monona County, Iowa, the valley is seventeen miles wide. In such an expansive valley, the Missouri was free to roam; and roam it did. Furthermore, the Missouri’s bed material between the James and Platte consisted predominantly of alluvium. Unlike stone or gravel, alluvium easily melts away when touched by water. Consequently, when the Missouri slammed against its alluvium banks, it encountered little resistance. Thus, the river was able to quickly alter its course.
The wide valley floor and the river’s alluvial bed explain not only the Missouri’s propensity to wander, but also why the river channel through western Iowa and southeast South Dakota held so many snags. The marauding Missouri frequently bowled over stream side forests and dumped the uprooted trees into its channel.
John Luttig experienced the Wild River’s instability firsthand while camped along the Missouri in what is today Monona County, Iowa. On July 4, 1812, he wrote, “…a thunder storm arose at 2 in the Morning and the Bank of the River where we camped fell in upon us momently. Mr Manuel Lisa was nearly drowned in his Bed, and we had to run off….”
On May 10, 1843, Edward Harris wrote in his journal of the Missouri’s wandering ways along the reach through western Iowa. He stated, “…we passed the old site of Council Bluffs. Two years ago the river passed close to it, but it has cut itself a new channel and left this splendid situation near two miles from its present channel.”
On April 13, 1850, Thaddeus Culbertson viewed the Missouri’s snag-filled channel near today’s Vermillion, South Dakota. “The Missouri here is full of snags; indeed it is so at almost every point where I have had a chance to look at it; the higher we go up, the worse it appears to get, but the danger from these is of course decreased by the high water; every few miles places can be seen where the river has changed its channel, sometimes in one year moving off a mile or two from a place where a good channel had been….”
In the 1930’s, U.S. Army Colonel George R. Spalding warned Army leaders not to build the navigation channel through western Iowa until the river’s floods had been checked by upstream dams. Spalding worried about the Wild River’s ability to quickly jump its banks and alter its course. He believed the river would outflank and destroy the Army’s pile dikes and revetments. The leadership of the Army Corps ignored Spalding and built the navigation channel to Sioux City.
In the 1940’s and early 1950’s, the Missouri south of Sioux City, as Col. Spalding had predicted, washed away over a hundred million dollars worth of pile dikes, revetments, and willow mattresses. By the early 1950’s, the Missouri in western Iowa had reverted to what Army officials referred to as a “wild state” – meaning it had busted out of the Army’s navigation channel and flowed unimpeded across its valley floor.
After Fort Randall Dam went into the Missouri in the 1950’s, the Army rebuilt the navigation channel to Sioux City. And although it had been pegged down with pile dikes and revetments, the Missouri in western Iowa and southeast South Dakota remained inherently unstable.
During the floods of 2011 and 2019, the Missouri through western Iowa broke out of its navigation channel in dozens of places. The Army responded to those two floods as it had to the floods of the 1940’s and 1950’s – it rebuilt the navigation channel to Sioux City. But if history is any guide, we can be certain the Missouri at some future date will again dismantle the navigation channel and flow once more as a Wild River.