With the 2011
floods of the Mississippi river there's real
concern that the Mississippi might jump
its channel at the Old
River Control Structure and take a shorter path through the
Atchafalaya basin, changing the structure and economy of half of
Louisiana. In the Internet discussion an astonishingly beautiful set of
maps from 1944 keeps turning up.
The maps are from the "Geological Investigation of the Alluvial Valley
of the Lower Mississippi River", a report by Harold Fisk (Geology
Professor at LSU) for the Army
Corps of Engineers. They did a huge amount of research on the history of
the river course, tracing 20 "stages" of the river course going back
some 2000 years. Accompanying 170 pages of sometimes dry text and tables
are these fifteen beautiful maps, a tangle of ropes showing the
historical Mississippi. Each colour (or stipple) is a former river path
and with some squinting you can work out the specific flow of the river
in, say, 1765. The real message is the aggregate of all those historical
courses, the unmanageable chaos of river meanders.
The report and maps are available for download from the Army but the files are big and pretty unwieldy. I've resized the rectified TIFFs to 25% and uploaded them to Flickr: you can browse them in this Flickr set. The one single image I recommend is Plate 22 Sheet 13: it shows the adjacency of the Mississippi and the Atchafalaya, connected by the Old River where the current water control system is threatened. For a different perspective, check out all the maps assembled into one long picture. It'd be neat to see a zoomable version of this to full resolution.
Update: why yes, it would be neat to have a zoomable version. Try it!
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