Tuesday, September 12, 2017

Industrial Revolution Archaelogical Subsurface Survey

I put in early in the afternoon with a rising tide and the resulting flood current helping to propel me up river.  Unlike yesterday, when I had no reason to be where I was, today I set out to check on a river that I haven't visited for awhile.  Right from the start I am flushing Great Blue Herons.  In fact, it seems as if I spot one about every two minutes or so as I head up into the primordial sections of the river.  Great Egrets are around as well, but the highlight is a Pied Billed Grebe that surfaces about threee boat lengths away. 
Pied Billed Grebe
It sinks (they have a flotation sac which allows them to sink without diving...no splash, no surface disturbance at all).  I stop paddling and wait for it to come up.  When it does it is over a hundred feet away and it shows only it's head and neck.  It sinks again....it comes up to check on me, sinks, comes up, sinks...fascinating bird.

Great Egret

I watch for the wild apple tree, but miss it on the way in.  The farther I go the more dead falls in the water there are to maneuver around.  I used to be able to get up to an old abandoned neighborhood, but the deadfalls have gotten worse and I hit my high point after an hour.

submerged cobble structure
What I did notice that is new to me is that there are cobble structures below the surface of the river.  The first that I spot looks like it had been the riprap on the outside of a bend, before the river flooded and washed the supporting bank away.  It's a long cobble dike paralleling the bank.  A bit farther I come across one that extends out from the bank, possibly a wing dam.  Wing dams are designed to funnel the river flow into a narrower channel...these were used on big rivers to keep a deep channel open for boat traffic.  The highest one that I find might also be a wing dam, or perhaps it crossed the whole river to create a deep pond.  It never was tall enough for water power.

On the way out, I add some Ravens to the count, plus a young bald eagle.
Garter Snake
I find the wild apple tree, pretty much where I thought it was.  The apples aren't ripe, yet.
On my next trip I need to bring a saw to clear some of the dead falls out.

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