Great Missouri River Flood of 2011: Made Worse by the Army’s Navigation Channel

Since the nineteenth century, the Army has built 8,300 “training structures” along the Missouri from Ponca, Nebraska, to the river’s mouth – a distance of 753 river miles.  The flooding along the lower Missouri River this summer is going to be made worse by those Army channelization works.

In the late nineteenth century, railroad companies monopolized transportation into and out of the Missouri Valley.  Farmers in the valley, and businessmen in Kansas City, St. Joseph, Omaha, and Sioux City, sought to break that monopoly by creating an alternate transportation route along the Missouri River.  To compete with the railroad companies, the Missouri had to carry deep-draft barges.  Only barges, with their large holds, could conceivably haul cargo at lower rates than the exploitative railroads.  But there were problems with the Missouri.  It possessed an average depth of three feet (too shallow for barge traffic); it meandered across its valley floor (creating navigational obstacles in the form of sandbars and shoals); and it filled its channel with snags during its annual April and June rises (as floodwaters cut into the river’s banks and toppled forest tracts).

For the Missouri to float barges, it had to be remade into something altogether different.  It had to be deepened to six feet and later nine feet; its meandering had to come to an end; and it had to be made to flow so fast that snags (which posed a threat to river vessels) could not plant themselves in the Missouri’s sandy bed.  To initiate those changes, the Army began channelizing the river in 1881, utilizing pile dikes (known today as wingdams) and revetments.

By 1940, the Army nearly completed a six-foot deep navigation channel from the river’s mouth to Sioux City.  But then floods began roaring down the valley.  The near-completion of the navigation channel to Sioux City coincided with an increase in flood frequency and heights along the channelized Lower Missouri.

The river jumped out of its confined navigation channel in 1941 and 1942.  In 1943, the Missouri flooded three times – a hydrological anamoly.  During the first flood of April 1943, the Army’s pile dikes and revetments funneled the Missouri’s floodwaters toward Omaha.  Channelization works so compressed the river that when the flood crest reached Omaha it nearly surpassed the record stage set in 1881, even though the volume of water was far less than the volume recorded in 1881.  Downtown Omaha sustained damage, as did Eppley Airfield, which sank under seven feet of water.

People recognized that the Army’s channelization works had contributed to the flooding.  Roy Towl of Omaha stated, “The April flood [of 1943]…was seven feet higher than the 1929 flood [before the channelization works went into the river], with the same amount of water going by.”

In 1944, the Missouri flooded two times.  A man familiar with the river and its hydraulic regime, J.A. Gray, made the following statement that year, “Now the river is gorged by piling dams, and the floods came [sic] twice a year – two last year [1943] and two this year [1944]…What about the future?  Can anyone deny [flood] conditions are getting worse every year?  Of course the floods will be worse.  Until the obstructions [the pile dikes and revetments] are removed there is no hope for the valley.

South Dakotan William Robinson, who had been involved with Missouri River issues since the early 1930s, became a vocal critic of the Army’s work along the Missouri.  He observed, “Soon after the installation of these pile dikes, property owners along the river, and [those] familiar with it, noted that floods were reaching higher elevations and overflowing property not ordinarily flooded; that higher stages were being reached each year although no abnormal volume of water was being discharged.”  Robinson continued, “The fact is that this threat of annual general inundation is wholly artificial and is due entirely to the changes made in the riverbed by the attempt to create a navigation channel…the flood threat should be relieved by restoring the river to its natural condition.”

Army officials, although aware of these criticisms, never admitted their channelization structures worsened the flood situation below Sioux City.  As a matter-of-fact, Colonel Lewis A. Pick, head of the Army’s Missouri River Division, refused to publicly address the role of the navigation channel in the floods of the 1940s.  Instead, Pick came up with what he believed would be a solution to the navigation channel’s reduced conveyance capacity.  His solution would also deflect criticism from the Army’s role in the flooding.  Rather than being the culprit in the recent floods, the Army would be the lower valley’s savior.

In August 1943, Pick proposed the construction of five earthen dams across the Missouri main-stem in North and South Dakota.  Like a good soldier who refuses to retreat, Pick rejected any suggestion that the Missouri navigation channel be de-constructed and the river allowed to re-enter its former side channels and 100-year floodplain – a viable flood control alternative to the construction of upstream dams.

Pick knew that without the Dakota dams, the Missouri would eventually destroy the Army’s coveted navigation channel.  And if the Missouri washed away that $250 million dollar investment, the Army would lose credibility with both the public and Congress.  Such a loss of legitimacy would threaten the Army’s hold over the Missouri River.  To prevent that scenario from unfolding, Pick wanted dams in the Dakotas.

Pick’s proposal to build dams in the Dakotas represented a brilliant, political counter-offensive.  He understood that those dams would enhance the Army’s engineering legitimacy and cement its political hold over the Missouri.

Pick’s proposed Dakota dams became the foundation for the Pick-Sloan Plan, which became law in December 1944.  But before Pick’s dams went on-line in the 1950s, the Missouri flooded along its navigation channel in 1945, 1946, 1947, 1948, 1949, 1950, 1951, and 1952.

On June 30, 1952, the House of Representatives held hearings on the Missouri River navigation channel.  Now-Chief of Engineers General Lewis A. Pick sat in attendance.  During the course of the hearings, the issue of flooding along the navigation channel came up.  House counsel John J. Donnelly confronted Pick.  He said, “The Corps of Engineers started their [channelization] work in 1927, and have spent more than a quarter of a billion dollars on it.  Their work did not have much effectiveness until you get into 1935.  There was a flood that year.  There  was a dry season in 1936 through 1940.  And then we have, every year from 1941 on, flood, flood, flood, flood, flood – all the way through…In 1929 [before the channelization works went into the river] the United States Geological Survey computed the gage reading at Hermann, Mo., [Missouri] at flood stage at 21 feet…The carrying capacity of the river at 21 feet was 315,000 cubic feet of water per second…In 1951, the river spilled its banks with 208,000 cubic feet per second.”  General Pick sat silently during Donnelly’s testimony.  He did not challenge the veracity of Donnelly’s assertions.  Rather, at the end of that day’s hearing, he merely asked for copies of Donnelly’s charts and graphs.  Once again, the Army refused to take any responsibility for its role in worsening the flood situation in the lower valley.

Pick recognized that only the Dakota dams could reduce the flood threat posed by the navigation channel.  Consequently, the Army feverishly pushed the construction of its main-stem dams.  The Army closed Fort Randall Dam in 1952, Garrison Dam in 1953, Gavin’s Point Dam in 1955, Oahe Dam in 1958, and Big Bend Dam in 1963.

Ignoring the past evidence that the navigation channel exacerbated flooding, and convinced that its Dakota dams would keep high flows from the confined lower river, the Army again initiated work on the navigation channel in the mid-1950s.  In 1980, the Army declared the navigation channel complete to Sioux City.

In 2011, the Army failed to keep high flows out of the navigation channel.  As a result, we now face a catastrophic flood because the channelized river cannot safely carry away the Missouri’s floodwaters.

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