Cut off from the rest EarthCache

This earthcache will require some time, mostly because of the drive you will have to do.

Erosion

Erosion is the process by which soil and rock are removed from the Earth's surface by processes such as wind or water flow, and then transported and deposited in other locations.

Valley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and head-ward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat, and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles and boulders can also act as erosion forces they traverse a surface, in a process known as traction.

Source: Wiki

History

Kaskaskia began in 1673, located in the fertile American Bottoms. At first favorably situated on a peninsula, in the late 19th century, the town was cut off from the Illinois mainland and mostly destroyed by repeated flooding and a channel change by the Mississippi River.

Kaskaskia flood in 1993

Marker on bluff

Erosional avulsion

Rivers can avulse due to the erosion of a new channel that creates a straighter path through the landscape. This can happen during large floods in situations in which the slope of the new channel is significantly greater than that of the old channel. Where the new channel's slope is about the same as the old channel's slope, a partial avulsion will occur in which both channels are occupied by flow.

Source: Photo

Avulsion typically occurs during large floods which carry the power necessary to rapidly change the landscape. Avulsions usually occur as a downstream to upstream process via head cutting erosion. If a bank of a current stream is breached a new trench will be cut into the existing floodplain. It either cuts through floodplain deposits or reoccupies an old channel. (wiki)

**Logging requirements**
DO NOT POST ANSWERS IN YOUR LOG.
Send the following answers to me via email.

1. The text "GC4QWMX Cut off from the rest" on the first line
2. What’s the elevation reading @ ground zero?
3. How wide was the old river channel? (Use waypoints “West” & “East”)
4. What’s the elevation reading @ waypoint “Center of it all”?
5. Based of your observation around town, do you think this town will be flooded again?
6. What’s the elevation reading @ waypoint “Elevation”?
7. Measure the current river’s, flow path, distance and subtract the 1740’s river distance of 13 miles. How much has the river shortened its path? (use waypoints “elevation” to “New river path”)

Sources

• Taylor, Troy. Weird Illinois. 1st. Barnes & Noble Books, 2005. 256. Print.
• http://en.wikipedia.org/wiki/Avulsion_%28river%29
• Beveridge, Thomas. Geologic Wonders and Curiosities of Missouri. 2nd. Rolla, Missouri: Missouri Department of Natural Resources, 1990. Print.