The Army Corps of Engineers and the environmentalists got a bad rap during the recent Missouri River flood. Specifically, Missouri Valley farmers blamed the flood on the Army’s supposed mismanagement of the Dakota dams as well as the U.S. Fish and Wildlife Service’s program of habitat restoration in the valley south of Yankton, South Dakota. The accusations, and their promotion by a sympathetic Midwestern media apparatus, are just not true. As a matter of fact, farmers are the ones who contributed the most to the recent flood.
Agriculture has the greatest influence on runoff into the Missouri and its tributaries. The reason for this is obvious – farmers own most of the land within the Missouri River’s drainage basin. Consequently, what farmers do with their land has a profound effect on the Missouri’s hydraulic regime.
Farmers have fostered flooding along the Missouri in ten significant ways.
- Soil Compaction. Heavy tractors, combines, and trucks compact the soil, hindering the absorption of rainfall and snowmelt and increasing runoff.
- Tributary Stream Straightening. In order to drain cropland quickly, farmers have straightened the Missouri’s tributaries. The re-engineered tributaries hurriedly push water into the Missouri, causing the big river to rise rapidly and often violently.
- Land leveling. Leveling the land with bulldozers removes even the slightest undulations. Those undulations once held rainwater and snowmelt. Their elimination means water all-too-frequently has nowhere to go but into the Missouri and its tributaries.
- Tiling. The tiles under so much Midwestern farmland capture runoff and then direct it toward the Missouri.
- Deforestation. Trees are natural reservoirs. They hold water in their leaves, branches, trunks, and roots. Trees and their leaf litter also slow surface runoff. Since the late 1840s, farmers in the valley between Sioux City and St. Joseph have been destroying the valley’s forests to increase their crop acreage. A period of major deforestation occurred south of Sioux City between the mid-1950s and 1980. The consequence of felling the Missouri Valley’s forests, and the forests along its tributaries, has been higher flood flows.
- Herbicides. Herbicides kill unwanted plants in corn and soybean fields. Clean crop rows might boost the number of bushels harvested per acre, but they also increase runoff.
- The Missouri River Navigation Channel. Lower Valley farmers support the continued upkeep of the navigation channel south of Sioux City. They do so because in normal years the navigation channel’s rock-lined banks allow them to farm to within feet of the water’s edge. But the navigation channel worsens flooding in the Lower Valley because it lacks the conveyance capacity to safely carry away high flows.
- Loss of CRP Acres, Pastureland, and Prairie. Farmers have destroyed thousands of square miles of Conservation Reserve Program acres, pastureland, and native prairie since the late 1990s, especially in Iowa, Nebraska, the Dakotas, and Montana. CRP acres, pastureland, and native prairie all have a higher rainfall and snowmelt absorption capacity than plowed, planted, and cultivated cropland.
- The Levee System. Farmers were warned after the 2011 flood not to rebuild the lower valley’s levee system too close to the river. They went ahead and did it anyway. And so, to no one’s surprise, the levees failed again this year. Misaligned levees worsen flooding. If you need confirmation of that fact, look at the history of the Lower Mississippi.
- Climate Change. Modern industrial agriculture uses lots of gas-guzzling machines. As a result, the agricultural sector is a major emitter of CO2. All the CO2 wafting skyward from farm country is helping to bring on heavier rains, more severe snowstorms, and a more erratic Missouri.
Although we know why the Missouri floods, don’t expect fundamental change along the river, or across its drainage basin, anytime soon. Rather, you should expect continued flooding.
Industrial agricultural is a juggernaut; and its rapaciousness isn’t going to be easily stopped, or even slowed. As for its army of faithful followers, they show no signs of curtailing their drive toward maximum production and maximum profits, even though those twin goals, and the manipulation of the land necessary to achieve them, fosters catastrophic flooding along the Mighty Mo.