Entrenched Meanderment

Entrenched meanderment?  What in the world is OZB going on about now?  Beveridge gives a wonderful explanation of the meandering nature of virtually all Missouri Ozark streams in “Geologic Wonders and Curiosities of Missouri”.  Within, he provides a few fascinating geological hypothesis as to the hows and whys of streams forming in such a manner with some of the hardest rock on the planet as their bed.  Think about it.  How and why would streams form in rock like this, with very little floodplain, steep cliffs/bluffs and not be straight?  Pick up Beveridge’s book to read of these hypothesis as well as learn about narrows, cutoffs and lost hills – the geologic features that are formed by these entrenched, meandering streams.

Two streams with an entrenched meandering environment on public land I have known and loved for a while.  These are the Meramec River at Vilander Bluffs N.A. and Jam Up Cave/Bluff on the upper Jacks Fork.  These are always worth a visit.  While flipping through Bryan Haynes’ book recently, I came across a panoramic painting of his that I have admired.  I saw the title: “Lee’s Bluff”.  Having never heard of this feature and the fact that his image was such a dramatic scene, I assumed that this must be found in some western wilderness, far from being a day trip destination.  I went ahead and searched the web, and to my surprise discovered this was in Missouri, along the St. Francis River and smack in the middle of those lovely St. Francois Mountains.  With Steve wearing his best navigator’s hat, we found the location pretty easily on a blustery, winter’s day.

Here’s an overview image taken with a 15mm lens.  You can see the features typical of a meandering entrenched stream, the steep bluffs formed on the outside of the bend and gentle sloping floodplains on the inside.  In the direct center you can see the “incipient lost hill” as described by Beveridge.  One day the “narrows” on the far side of that hill will succumb and a “cutoff” will form, straightening the river.

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   The sky was a constant change on this day.  Here Steve poses while the sun breaks through an opening.

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Climbing around on the steep, sharp rocks of the bluff we came across an ancient skeleton of an eastern red cedar.  The relative youngster below looks ready to take its place in another couple of centuries.

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Professional schlepper, navigator, and photo model.  I’m sure glad Steve works for free!  😉  Here he stands next to the old tree to give the image some perspective.

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The image below is probably my favorite from this day.  One of the visual beauties of these types of entrenched stream environments is that there are two S-curves in each one.  You just have to figure out where to place your camera to take advantage of it.  Under the right light and weather conditions, this place holds a lot of photographic potential, not to mention the potential for reflection and wonderment.

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