Not clear to me from what I've seen how the spillway might be failing. Maybe it's getting undercut somehow? But anyways here is the rating specs vs. current flows.
"Dossey said the emergency spillway was rated to handle 250,000 cubic feet per second, but it began to show weakness Sunday at a small fraction of that. Flows through the spillway peaked at 12,600 cfs at 1 a.m. Sunday and were down to 8,000 cfs by midday.
Read more here: [
www.sacbee.com]"