Ancient Courses of the Mississippi River Map

One of the most fascinating maps I've seen are the Ancient Courses of the Mississippi River by cartographer Harold Fisk for the Army Corps of Engineers.

The maps (they run up and down the Lower Mississippi River), show the present (c.1944) course of the river, as well as how that course has changed over time through stages. The river changes course continuously, as do all rivers, and especially so in the case of when major floods, earthquakes, or other disasters that may alter the river occur.

Fisk is as much of an artist as he is a scientist, as these maps are incredibly beautiful and yet perfectly convey how the Mississippi River has changed over time.

1944 Fisk Map of the Mississippi River (Plate 32, Sheet 6) (Amazon Link)

The maps represent the Meander Belt of the Mississippi, according to Public Domain Review, and are primarily focused on the last several millennia of changes. As the Mississippi and Missouri Rivers are the primary rivers of the third largest river system in the world, the stage changes of the Mississippi are immense, and viewing these maps for the first time gave me a profound sense of wonder for how natural processes change. 

A scale for how many maps exist in the series, each created by Harold Fisk.

In the book Twain's Feast, author Andrew Beahrs wrote of the Mississippi, "It transformed under the stars and in pitch blackness, in gray mist and by the light of a multitude of moons ... [it] had a new story to tell every day." (NPR)

NASA provides context below for the Fisk maps and its comparison to 1999 satellite imagery. Even going back very recently in geologic time shows the complexity of the River!

From Mississippi Meanders. (NASA)

Less poetically, as the landscape around them changes, rivers, or the waters that make them up, take the path of least resistance, which changes as rocks and sediment move around or are eroded over time. This process can create new channels of flow, and abandon old ones, resulting in natural phenomena like oxbow lakes, or in the case of Kaskaskia, islands within the river, which is why the once former capital of Illinois is now West of the Mississippi River.

You can see remnants of the Mississippi's ancient courses on Google Maps. Floods in 1844 and 1881 created the main channel of the river today, while older flows mark up where the boundary between Illinois and Missouri were settled.

While rivers change their flows, state boundaries do not, and thus there are several examples across the US of a state boundary that was decided where the river flowed at that time that have since created examples like Kaskaskia above, where the main course of the river does not match the boundary of the state.

As you can see, the Mississippi River is a continuously evolving natural being, and while in the last couple hundred years humanity has straightened, dammed and changed the river, much like with most bodies of water, without human intervention it would continue to change and evolve naturally. Mark Twain compared the river being straightened for navigation to the change going on throughout his lifetime, "everything was changed... That world which I knew in its blossoming youth is old and bowed and melancholy now; its soft cheeks are leathery and wrinkled, the fire is gone out of its eyes and the spring from its step. It will be dust and ashes when I come again."

Seeing these maps made me want to begin mapping the changing courses of rivers, much like how the changing alignments of railroads is one area of focus on our Abandoned Railroad Map, but the sheer complexity and time that the river has existed make that a nearly impossible task. Finding all the abandoned railroads and realignments is difficult enough, on a system that has existed for just about 200 years at this point. 

The Mississippi River, on the other hand, is at least 5 million years old, if not much older, and thus the scale of change on even a thousand year timeline only makes me curious to see how it has changed in geologic time!

Since Fisk's maps, LiDAR imagery has allowed us to further visualize changes in river courses, as shown below by Dan Coe Carto:

"Lidar-derived image of the Mississippi River along the border of Arkansas and Mississippi, southwest of Memphis, Tennessee." (Dan Coe Carto)

The same area as the above LiDAR image from the Fisk map.

Thanks as always for reading!


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