How do they get the concrete and rock to the hole? There is no access to it.
They plan on airlifting bags of riprap. I wonder if they could launch some barges across the lake where they have main road access and a marina loaded with materials and a trackhoe, or to send a laden barge with material and sink it against the emergency spillway while the water is high, the only access road is completely washed out but could be filled in within days.
They need the dam lowered a lot to give them several weeks of emergency repair time, and its just not coming.
Btw, i manage a concrete batch plant and have a concrete boom pump not too far in Auburn just east of Sacramento so i have a lot of interest in all of this, possibly i might be physically involved.