Prehistoric Kennebec River channel

This summer I found this old, prehistoric channel of the Kennebec River about 1/4 mile from the river at Five Mile Island in Vassalboro, Maine. I believe that this old channel is still a meadow because when the Edwards Dam impoundment was in place from 1837-1999) spring flood flows would overtop the bank and fill the channel once or twice a year.


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The old channel is the light, non-wooded vertical patch in the upper center of this aerial photo on the right side of the river. Below is a terrain map.


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Below is a closer look at the old channel, which is now a meadow with scattered trees. The entire area is criss-crossed with beaver paths.


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The prehistoric channel at Five Mile Island, prior to be cutting off, probably resembled this existing side channel on the Kennebec River in Sidney, about six miles upstream. This aerial photo was taken at very high flows and shows a side channel separated by a "teardrop" shaped gravel bar island from the main channel. This area was completed filled with silt and debris from the impounding effect of the Edwards Dam and is only now starting to regain its natural channel configuration, as spring floods remove the 160 years of in-filling from the dam's construction in 1837.

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A mile farther upriver, on the Vassalboro side, is another set of prehistoric side channels, which are now wooded swamps separated from the river by the railroad grade which cuts through them.