1964 Coffeen Lake Dam Near East Fork Shoal Creek

(Satellite)

This dam was built to provide cooling water for the Coffeen mine-mouth power station.

Satellite

The dam was actively spilling water when this satellite made a pass over it.

Satellite

NationalDams

While looking at a topo map to find the name of the railroad that served the power station, I noticed that there are some canyons in this area. I was not aware that there was this type of topology in Illinois.

1947 Hillsboro Quad @ 1:62,500

This is a comparable area from a later map. (A sliver on the east side of this excerpt is the 1947 map because the newer map covers a smaller area.) It is the canyon of the McDavid Branch that is now filled with water. So this lake has a larger volume of water than I would have guessed. I thought that was important so that the increased volume of water would dilute the heat. But we will see shortly that the heat stays on the surface and doesn't get diluted.

1974 Coffeen Quad @ 1:24,000

The power company owns the dam, but the Illinois park system manages the recreational resources of the lake. The land between the two branches is restricted and the land not used by the power company is a wildlife reserve. [brochure]

I learned from the Kincaid Power Plant that the canal between the two branches of the river is used to discharge cooling water.

Satellite

According to a tour of the plant, this small building houses the intake pumps.

Satellite

The plant reuses its water because it can flow down the east branch and back up the west branch. Despite the 1200-acre lake having a large volume because it fills a canyon, the water can get too hot in the Summer. So in July 2000, a 73-acre cooling basin and 24 cooling towers were put in service. [ameren] And I noticed that a new spillway that was better designed to aerate the water was added.

Satellite