Wow, that sounds like a tough engineering problem. That is a LOT of water to move, least of which is the pressure of water flowing around the bends in the pipe, or the suction at various points. It has to be pipe well rated for that flow and pressures.

If you have the room for it, point the outlet straight up with a surrounding pool of water and/or concrete pad to disperse the energy. I am no expert, but that is what they do with the outflow of canal lock pipes up here which move TREMENDOUS amount of water very quickly.

I would sweat with that much watershed and a hurricane or TS heading my way. It may not happen often, but you do need to plan for the worst with that much water which could burst and harm those downstream.