Thursday, June 10, 2021

1974 Brookville Dam near Brookville, IN


While researching the Whitewater Canal, I could not help but notice there was a big lake north of Brookeville, IN. Because it has a straight edge along the south end, I knew I could zoom in to find a dam.

USACE Master  Plan, p1

"The earthen dam was constructed in 1974 by the United States Army Corps of Engineers with a height of 181 feet and 2800 feet long at its crest." [shops-net]

"The outlet works has a main gate discharge capacity of 7,900 cubic feet per second (cfs) at flood pool (elevation 775 feet msl)." The watershed is 379 square miles. [USACEMP, p11,12]


The Master Plan was about land use. I could not find anything about dam operations. I think the Summer level is what they maintain during the summer for recreational use. The Water Supply level is what they allow it to get down to for the Winter so that they will have more space to absorb Spring floods while maintaining enough water to supply water during a drought.

USACEMP, p9 at 100%

The thing that struck me by the above map is that the flood pool didn't spread out very much, it just went further up the river. That must mean that the lake is in a canyon. I zoomed in to confirm that the flood pool is not a lot larger than the recreational pool along the sides.

USACEMP, p9 at 250%

This post confirms my theory that "Water Supply" is the Winter level and they actively release water to get down to it:
October 14th marks the end of summer pool. On October 15th we will begin gradually releasing 7 feet of water to attain an elevation of 740 feet to get to winter pool. If you have questions about boats or boat docks please contact the IDNR at 765-647-2657.
-Ranger Beard

But the water does come inland at the tributaries.
USACE posted

Is the sign below the one we see in the photo above?

I positioned this on my monitors so that I could get as many pixels as possible of the text.
Traci Markcum, Aug 2019

Digitally Zoomed

Kathy Cobin, May 2019

A Linda Hall video of water coming out of the 12' conduit in Feb 2019  Once again, 2019 was a wet year in the USA. It looks like it has room to spare so I doubt if the emergency spillway, which is 34' below the top of the 181' tall dam, has ever been used. What looks like a hydraulic jump is where the water hits baffle blocks in the spillway.

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