Apalachicola River Erosion
Erosion is the gradual wearing away of land surface materials, especially rocks, sediments, and soils, by the action of water, wind, or a glacier. Usually erosion also involves the transport of eroded material from one place to another, as from the top of a mountain to an adjacent valley, or from the upstream portion of a river to the downstream portion. Many rivers are straight and have equal erosion on both sides. Many rivers meander and have curves and different erosion patterns. The Apalachicola River here has a couple of distinct features that set it apart from standard meanders.
Standard Meander
In a standard meander bend, the water flows faster on the outside of the bend, and the extra energy pulls from the side (cut bank). The water on the inside of the bank has a slower flow and the material is deposited (point bars). As more material is taken from the cut bank and deposited into the point bar, the velocity differential increases, and the effect is even greater. As shown by the images on the right, the deepest point in the river is closest to the cut bank and does not follow the center of the channel.
Torreya Apalachicola River
There are two curious elements associated with the River here that make it different from a standard meander. The sand and normal soil in this area has eroded quickly in this area, while the red clay is more dense and holds together much better. There is a differing pattern of erosion in the cut banks and also the point bars, which is dependent on soil type and the mix, as all types are seen in this area.
The second item is the impact man has had on the River here. To continue barge traffic, Florida has undertaken an aggressive dredging project, which has impacted the standard deep point pattern from a meander to keep the deepest point in the center of the channel. The dredging can be seen throughout the river and the point bar differences can be seen as man tries to change the standard erosion patterns.
Logging Requirements
Send the following to me through the e-mail link. Do not post the answers in the log, even encrypted.
· What is the predominant soil type at the cut bank directly in front of the GZ (clay, sand, soil)?
· Look upriver at the point bar. Estimate the width of the bar and any impact you see that man has had on the formation