By SANDRA RENDGEN
Oh, the Mississippi. The „Father of Waters“ is a heroic beauty with an eventful history, famous for its tendency to meander. At times, it poses a major threat to the people living along its shore. The list of Mississippi River floods is long and rather scary. It also happens to be a major commercial waterway, and these two aspects are at the heart of why the US Army Corps of Engineers has long been in charge for works in and along the river: in order to shield residents from floods, and to procure unobstructed navigation.
This mind-blowing piece of cartography was made for the engineering corps. It is one in a series of fifteen sheets, which accompanied an extensive report issued for the corps by Harold Fisk in 1944. A professor of geology in Louisiana, he was fascinated with the meandering process of the Mississippi and sought to map it. The report was the result of three years of intense field work, which saw Fisk travelling some 650 miles along the course of the river together with a colleague, investigating layers of deposits and recording historical river beds.
Since 1836, the river had been subject to minor and major interventions from the engineering corps, both to ensure navigation and to ward towns and cities from floods. However, measures such as building levees, channeling or excavating the river would at times elicit undesired effects and were not able to hinder the 1927 disastrous flooding. Fisk’s research can be interpreted as an effort to better understand the intricate and damageable ecosystem of the river – particularly in its tendency to continually create ever new courses for the river bed.
On a black and white base map, Fisk plotted both the current course of the river (white) as well as all historical stages he was able to document (various colours and patterns). This totalled up at no less than thirty stages of differing river courses – and this is what it looks like when plotted. Fisk used an intricate color system to mark the various stages, but of course – human visual perception is slow to differentiate between so many similar tones. The legend neatly labels the various courses – many of which, by the way, were reconstructed using aerial photographs.
Of course, plotting thirty different stages on one map leads to a lot of clutter, the stages are entangled and cover each other. Except for the current river bed, the eye can’t completely follow one course or the other. So what then is the use of printing these mad, cluttered maps in which the main information is hard to decipher in detail?
Well, what they can do is condense an extremely long historical process (and its ecological consequences) in one unified view. The meandering of the river has long been well known, but these maps are famous because they create a visual for this ongoing process, an image of this constant meandering, the constant cutting-off and opening of new river beds. These maps make you look at thousands and thousands of years of natural history. They make you see the river meandering. What else could you wish for in a good visualisation.
Harold Fisk’s report and the high resolution oversize plates from the reports (incl. the maps) can be downloaded from the website of the US Army Corps of Engineers. If you want a print of those hanging over your bedside, head over to Society6.
Sandra Rendgen is the author of two bestselling books on data visualisation and infographics, both published by Taschen. Currently she is getting lost in the history of data visualisation.