Lockport Powerhouse, and it is normally not used. It was turned on for a tour group I was in.
Modern spillways use an Ogee curve at the crest (top) that starts horizontally and gradually curves to the desired incline so that the flow of water over the crest remains a laminar flow. This diagram below illustrates that the computation of that curve is non-trivial. There are three pages of text describing the quantities in this figure (pp 5-7).
|Dr. Pierre Julien's 11-11-14 handout entitled CIVE 401-Notes on Spillways|
|20160603 3358, Wilmington Dam|
|20170121 7776, South Elgin Dam|
This one has a sharper curve in the middle of the flow than I normally see.
Back to the turbulent flow of the 1907 spillway.
The water remains "churned up" through most of the distance of the discharge canal.
Lockport Powerhouse Spillway has more photos of this spillway.