Wednesday, December 30, 2009

Saturated Creek Bank

In this section, the creek has a bit of a flood plain in which to meander. A limestone mass, just out of frame to the left, causes the water to make an abrupt turn towards the right bank. Healthy sized gravel bars have developed on the inside of the curves.

Overland flow falling over the right bank leaves the soil saturated and more susceptible to erosion. The bank has moved over four feet in the last 20 years.

There’s a deer highway on top of the bank that further accelerates the erosion. The combination of creek water rounding the curve, saturated soil on the bank, and deer damage on top of the bank makes it unlikely that this bank will stabilize anytime soon.

The source of the water is about 100 feet from the creek bank. A large wet area has developed where the water slowly flows across the flood plain. I’ve thought that this area might display vegetation more typical of wet areas, but the seasonal wetness is strictly a winter phenomenon and doesn’t seem to significantly influence plant growth.

Here’s the source of the water flow. Rain that fell on the neighboring hillside has completed its subterranean journey and is surfacing from these small holes. Disturbing the sediment helps trace the rate and direction of water movement. Above and to the right of the holes, rapid water movement quickly replaced the cloudy water with clear. Left of the hole is a quiet backwater that is taking a long time to clear. Below and right is slower moving water that still shows the streaks of sediment moving away toward the lower right side of the photo.

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