Sunday, January 22, 2017

Carpentersville Dam on Fox River

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Like many of the towns along the Fox River, Carpenteresville exists because of a dam. In this case a dam was built in 1838 and a saw mill was built in 1839. East and West mill races were dug in 1844. If you look at a satellite image, the west one has silted in but the east one still contains water and control gates near the entrance.

I did this trip on the first clear day in over a week. That is, it had rained every day for a while before I took this photo. So I caught it with a heavy flow in the river. This theory is confirmed by a couple of Goggle Photos that show more typical river flows: Oct 2016 (note a fisherman is standing in the river) and Dec 2009.

I wonder if this dam replaced a "rolling dam" (drowning machine) such as the one in Wilmington, IL. The short sharp drop onto a gentle slope looks like it might avoid the rolling boil and erosion created by the dams that simply have a sharp drop.
A comparable view in Apr 2016 shows a similar heavy river flow. But a heavy flow in Spring is more expected than this heavy flow in January. (Some more Apr 2016 photos.)

I made a short video to capture the sound of the water flow and the turbulence.
After I took the top picture, I stepped back to catch the safe viewing platform that the Forest Preserve has provided. And I was reminded that dams attract bird watchers because the turbulent water does not freeze so it attracts birds, including bald eagles.
The Forest Preserve has mounted some interpretive signs. I found this part on ice harvesting particularly interesting.

The warning sign indicates this dam is an old fashioned "rolling dam." The PVC pipe is for fish line disposal.

I'm reminded that fishing license fees help finance maintaining access to rivers. In some places this does make it easier to get pictures of dams and bridges such as building parking lots.
This was the entrance to the west mill race before it silted up. I took this picture to record the water level. I wonder how much of this land is exposed during the Summer when the water flow is slow. "The dam created a large pool of water so that even during a drought enough water would be available to divert into the mill races and run the mill wheels. The level and speed in the race leading to the water wheels was controlled by a sluice gate at the entrance and outlet.... The gates were raised and lowered depending on the river's level and the mill's power requirements." [Forest Preserve interpretive sign]

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