[mad_as_he$$]

That is the reason I found the small scale flow tests from the design phase so interesting and concerning at the same time. Trying to narrow the flow after the water is released is just poor fluid(s) reality and against common physics principles. If any thing the spillway should get wider. AND who the heck decided to put the drop off in the spillway. It should of been a straight line from the gates to the bottom. Probably was chosen to save moving some additional earth. Well they wound up moving it anyway along with 900,000 additional yards at 100+ times what it would of cost in 1967.

[KC Burke]

The dissipation blocks and the little flip at the end are meant to be energy dissipation features to try and impact the river less. There are even dams with a giant flip ski jumping spllway.

The dam height here means the spillway has to be long and energy generated is huge.