Worst case is the emergency spillway fails which could breach to 30 feet below current water level. Very bad, but will not affect main dam, which is 770 feet high (think Biblical).
Bigger problem is more rain expected late next week. A warm storm could greatly increase inflow to resevoir.
They won’t have time to fix it.
I was going to say that the main dam doesn’t look threatened just the spillways that are suppose to direct the outflows in an orderly fashion without surrounding erosion to the landscapes around the base of the dam. Are they hinting that this erosion may threaten the base of support of the main dam itself?