For instance, steamboat crews felled the valley’s forests to provide fuel for the hundreds of steamers that worked the river. The loss of lowland timber caused the Missouri to rise higher, faster, and more frequently than it had in the years before the advent of steamboat traffic on the river.
Valley farmers also contributed to deforestation. They knocked down the Missouri’s wooded fringes to acquire timber for log cabins, fence posts, roofing shingles, and crude furniture. Settlers burned kindling in cooking and heating fires.
Floods passed down the valley in 1844, 1857, 1858, 1862, 1867, 1872, 1874, 1875, 1878, and 1881 – these, not coincidently, happened to be the same years settlers filled the valley bottomlands between St. Joseph, Missouri, and Montana Territory.
The pace of environmental change in the Missouri Valley quickened in the late 19th and early 20th centuries. The expansion of agricultural production all across the bottomlands, in concert with the Army’s channelization project, remade the Missouri south of Sioux City, Iowa.
Prior to European-American settlement, vast stretches of the Missouri Valley existed as wetlands – what settlers referred to as swamps, sloughs, or swamplands. Wetlands came in many shapes and sizes. Oxbow lakes represented a common wetland type. They formed when the Missouri cut-off its long, curving bends. Notable oxbow lakes in western Iowa include Blue Lake (west of Onawa) and Brown’s Lake (west of Salix).
The Missouri also formed wetlands during its periodic floods. Before the laser-leveling of the valley floor in the late 20th century, the Missouri’s immediate banks stood at a higher elevation than the nearby lowlands. As a matter of fact, the valley lowlands sloped downward from the river’s banks to the bluffs on either side of the river. Each year, during the river’s April and June rises, the Missouri overtopped its natural banks and sent water cascading down toward the valley walls, where it pooled in former channel areas and scour holes. Even after the flood crests passed downstream, floodwater remained atop the valley floor because the Missouri’s high banks prevented the return of floodwater back to the main channel. The water left behind by the river’s inundations became wetland areas.
Occasionally the Missouri created wetlands by excavating holes, temporary channels, and shallow depressions in the valley’s soft alluvium.
The journals of settlers, and those who traveled up the Missouri on board steamboats, frequently noted the profusion of wetlands in the valley.
During the initial settlement of the Missouri Valley, European-American agriculturalists avoided occupying the valley’s low spots. Farmers left the wetlands to the water. They built their log cabins, barns, and cattle pens atop knolls or narrow ridge lines located across the valley floor – these high points were more secure from the river’s annual inundations Farmers planted their crops in areas with adequate natural drainage.
But in the 1890’s and first decade of the 1900’s, Missouri Valley farmers began to drain the valley’s wetlands. Farmers excavated ditches from shallow oxbow lakes and water-filled scour holes to the main river. They also placed clay tiles beneath low-lying areas to ensure that rainfall did not accumulate. Within a few years, valley farmers had converted thousands of acres of wetlands to cropland.
What became known as “the drainage craze” reached a fever pitch in the first decade of the 1900’s. A “New York Times” article dated September 23, 1910, stated that farmers in thirty Iowa counties had spend $15 million dollars ($379 million today) from 1904 through 1909 to drain their land. Farmers in Iowa’s other 69 counties had spent comparable sums of money during the same period on drainage ditches, stream straightening, and the tiling of cropland.
The loss of the valley’s wetlands came at a heavy environmental price. Wetlands had moderated the Missouri’s floods. Oxbow lakes, old channel areas, and ancient scour holes acted as natural reservoirs during flood episodes by storing runoff and preventing the Missouri from rising too high and too fast. Wetlands offered Missouri Valley residents natural flood storage areas.
The destruction of the valley’s wetlands worsened flooding along the river, especially in the valley south of Yankton, South Dakota. The Missouri went out of its banks in 1894, 1897, 1899, 1900, 1903, 1904, 1906, 1908, 1911, 1915, 1916. All of these floods occurred during the years of the drainage craze.
If some Missouri Valley residents understood the root cause of the flooding, they did not admit it in public. Not one of the valley’s newspapers made any connection between the actions of valley farmers and the floods. No one urged the reestablishment of the lost wetlands as a means of mitigating floods. Instead, valley farmers lobbied the federal government to channelize the river. They incorrectly believed a narrower, straighter, faster-moving Missouri would reduce the flood threat. Thus, in subsequent years, the Army channelized the Missouri to create a navigation channel that would carry both barges and floodwaters.