1923 Lake Decatur Dam on Sangamon River in Decatur, IL

(Satellite)

Staley had already built a pump house in 1919.

Street View, Oct 2022

Decatur Illinois - City Government posted four photos with the comment:

100 Years of Lake Decatur History: Equipment

The Lake Decatur dam has an earthen and clay core encased in concrete. In order to more efficiently move the enormous amount of dirt, clay, gravel, concrete, and other construction materials, the dam's contractor, L. M. Cope & Son, had a railroad spur built.

Fascinating to see the equipment used in the 1920s!

Each week leading up to the Centennial Lake Fest, you'll see another post about the awesome history of our lake. These weekly posts certainly won't cover ALL the history, so check out the "100 Years of Lake Decatur History" group to see more posts and share your own experiences/history - https://www.facebook.com/groups/899265747792819

Kristopher Isaac Barrington shared

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DecaturIL
It was constructed during 1920-23 and the Lake Decatur filled up during the Summer of 1923.

DecaturIL
This view is from what is now 20' under water. It shows the original sluice gates. The round intake covers on the right were inlets to the original water treatment plant on Lincoln Park Drive.

DecaturIL
The Lake Decatur dam has an earthen and clay core encased in concrete.

Originally, the rim of the dam was lined with sluice gates.

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In 2010, "bascule gates" were installed. I would call them wicket gates.

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Here the south half is open, but the north half is still closed.

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They definitely favor using the south side of the dam for spilling water. According to street views, they added that "railing" across the top between Mar 2012 and Nov 2015. I don't know why.

wandtv, Jul 25, 2022

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In 2016, the city approved $102k for an emergency action plan.

0:54 video @ 0:09

A couple of postcards showing it spilling water across the whole dam

May 1977: an Oakley Dam was proposed upstream on the Sangamon River to offset the water supply capacity lost to silt in Lake Decatur. But some professors at the University of Illinois fought the dam for 30 years and that was enough for inflation to decrease the cost-benefit ratio of the dam below 1. That ratio killed planning for the dam.