That should cut down on the cost of demolition!
Realistically, the bottom will be torn out and replaced. The top will either be repaired or replaced. A good assessment can't really be done until the water is down enough that they don't need to use it for a while. Which also means getting the plant back on line.
The entire chute should be rebuilt. The upper portion is aged and has numerous cracks and patches. Secondly, and most importantly, is a design issue. The slope should be flat rather than a convex curve.