This year, the Missouri defeated the sophisticated and expensive hydraulic system built to contain it. Neither the Army’s gigantic earthen dams, high levees, nor its thousands of pile dikes and revetments could stop the Missouri from inundating its valley from Montana south to the state of Missouri. This is not the first time the Missouri has confounded the efforts of the Army to control it. As a matter of fact, the river has defied the federal engineers since the nineteenth century – and it will do so again. It is why the Missouri is known as the “Mighty Mo.”
Between 1891 and 1980, the Army spent $650 million dollars (in present-day dollars) to channelize the Lower Missouri from Ponca, Nebraska, to the river’s mouth. It utilized the most-modern engineering techniques and machines to narrow the river from an average width of 2,329 feet to a mere 739 feet. By building the navigation channel, the Army hoped deep-draft barges would utilize the river as a commercial route. However, repeated droughts, floods, a rapid current velocity, the tendency of the Missouri to shoal at its crossings, and more cost-effective truck and rail traffic contributed to the navigation channel’s failure as a transportation artery.
During the Dirty Thirties, the Missouri dropped so low that it did not possess enough water to float barges through its navigation channel. But rather than abandon the navigation channel to the whims of the river, the Army sought to regain a semblance of control over the stream. It built Fort Peck Dam to secure water for the navigation channel during the region’s periodic dry spells. This great dam repeatedly failed in its primary purpose. In the 1980s, 1990s, and again in the 2000s, the dam did not discharge reliable flows. By 2008, the resultant lack of water led to the near-disappearance of barge traffic on the Missouri.
The Lower Missouri experienced a flood every year from 1941 through 1952. The repeated inundations resulted from the reduced carrying capacity of the navigation channel. The Army so constricted the Missouri that it could not safely pass high flows downstream. Besides inflicting millions of dollars in damage on towns and farms, the floods pounded the Army’s training structures – destroying at least $125 million dollars worth of pile dikes and revetments. Instead of modifying the navigation channel to let the river back into its floodplain (which some officials urged at the time), the Army high command opted to build five more dams in the Dakotas. The Army hoped the Dakota dams would end floods in the lower valley and slow the destruction of pile dikes and revetments. The dams cost billions. But they did not stop flooding along the Lower Missouri. The lower river was just too narrow to hold much water. The Missouri went out of its banks south of Sioux City in 1960, 1971, 1973, 1984, 1993, 1995, 1997, 2010, and again this year.
After World War II, the Army constructed a multi-million dollar levee system in the lower valley. Those levees did not stem the river’s floods. Numerous levees succumbed to the Missouri in 1993. In 2011, the Missouri either overtopped or undermined dozens of levees between Sioux City and Kansas City.
The Great Flood of 2011 has clearly shown that engineering structures alone cannot halt floods along the Missouri. This year, our technology has failed us. More dams, levees, and reconstructed pile dikes and revetments are not going to solve our flood problem. As a society, we have wasted enough time and money attempting to check the flow of the Missouri with engineering works. It’s time to try something different. It’s time to consider non-structural solutions to the river’s flooding.
A few non-structural solutions to flooding along the Missouri include: the drawdown of the upstream reservoirs to a new base level; the restoration of millions of acres of native grassland in the Missouri basin to absorb rainwater and snowmelt; a moratorium on building in the river’s floodplain; the deconstruction of the navigation channel to allow the lower river to widen out and lower its future flood crests; the planting of bank side trees to hinder bank erosion; and the reestablishment of wetland areas.
There are those who would argue that without all of the Army’s massive structures, the flooding along the river would have been worse. Well, maybe or maybe not. It could be argued that because of the Army’s control works, the 2011 flood lasted far longer and inflicted far more damage than a traditional Missouri River flood of short duration.
Our long-held confidence in technology lulled us into thinking we were immune to the Missouri’s floods. But this year’s Great Flood has proven our faith in big dams, levees and channelization works to be misplaced.