History of Transportation
Early in the 19th Century, the US Army Corps of Engineers began its quest to tame the Mississippi River and make it safe for navigation. Below the confluence of the Mississippi and Missouri Rivers, there was adequate depth for the shallow draft riverboats and few impediments to river travel. But the upper river was quite a different story. Numerous sandbars, rapids, and obstructions made river travel difficult.
With the technology of the day, the Corps faced an uphill battle. The early efforts were limited to removing log jams and other obstructions from the main channel. But soon, new techniques were developed that assisted in the effort. In the late 1860s, Congress appropriated $4 million to remove troubling rapids at the mouths of the Des Moines and Rock Rivers, which limited river travel from Keokuck, Iowa to several miles upstream of Rock Island, Illinois. These were the first major construction projects on the Upper Mississippi.
For most of the 19th Century, the Corps' primary focus was on letting the river do as much of the work as possible. They accomplished this by building thousands of structures known as wing dams and closing dams. Each of these served a single purpose; to force as much of the river's flow into the center of the main channel as possible, where the increased current would carry away sediments and keep the channel deep and free of obstructions.
Wing dams are brush and stone structures extending from the river bank toward the channel, usually at a 90 degree angle. Wing dams were built fairly close together, often with only several hundred feet between them. Closing dams, similar in construction, were used to block the connections between the main channel and the hundreds of backwaters and side channels that wove their way across the river's floodplain. Although these structures were built more than 100 years ago, they are still common features on the Upper Mississippi.
By the dawn of the 20th Century, the wing dams and closing dams, along with periodic dredging, allowed the Corps to maintain a navigation channel four feet in depth all the way upstream to Minneapolis. In 1910, he depth of the channel was increased to 6 feet. With these simple methods, maintaining the channel at a greater depth would be too difficult and expensive.
Around this time, the economy of the Upper Midwest was changing. Logging in the region was all but over, and the growing agricultural economy was joined by tremendous growth in manufacturing. Increased transportation needs brought about by the First World War revealed the limitations of the railroads, drawing more attention to the waterway system.
Business interests in the Upper Midwest began to look at the Upper Mississippi as the answer to their call for cheaper transportation alternatives. But the use of the river for moving goods was limited by the six foot channel depth, and increasing it beyond six feet was not feasible with current methods. The solution, they decided, was the construction of dams to raise water levels and locks to pass the barges from one pool to the next.
By 1928, the Corps was considering the creation of a nine foot navigation channel from St. Louis, Missouri to Minneapolis, employing a series of locks and dams to manage water levels. The Corps' initial assessment of the economic benefits of a nine foot channel were not favorable, but intense political pressure in Washington moved the project along through the planning process.
As the Corps worked developed plans for the nine foot channel project, supporters brought pressure to bear on Congress to secure the funding for construction. By 1930, the Upper Midwest business interests finally won. Despite the lack of a completed report from the Corps, Congress authorized the project.
Despite the blessings of Congress, however, supporters of the project faced one final challenge. President Herbert Hoover opposed the project even though he signed the bill containing its authorization, and he successfully blocked funding for construction for the next two years. Pressure from Upper Midwest business leaders and Members of Congress failed to alter Hoover's position. Ultimately, it took the collapse of the US economy and a changing of the guard at the White House to move the project forward.
to be continued...
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