One thing in their favor is that the ravine is truly carved to mostly bedrock. I don’t think it will erode nearly as bad as it initially did. Which means that there will be a lot less debris moved.
My thought, for a temporary repair (and this is just a WAG), would be to build up the ground at the end of the good section of the chute so that the water can gently fall down at an angle rather than falling hard and beating the ground below. Use the path it’s been following and harden it as much as practical. Use that until a new spillway can be designed and built.
Like I said, a shot in the dark. I have no idea how realistic that might be.
The emergency spillway to the left is truly an extreme emergency use only tool.
Yeah.
I see the main spillway as a big problem,but not necessarily imminently threatening to life.
I see the emergency spillway as a YUGE and imminently threatening problem.