I have a beef with that graphic circulating... it places the responsibility for the failure with federal regulators by misrepresenting the facts. The federal regulators did NOT reject improvements to the eSpillway, the refused to require the state to do so as a condition of re-licensing. The federal regulator does did not prevent the CA DWR from making improvements or from performing other necessary improvements, repairs, and maintenance. They left CA to prioritize infrastructure spending as they saw fit, letting CA prioritizing spending at the Oroville damn as they saw fit, given other spending priorities... CA just chose unwisely.
If I were an engineer on that dam, I think I would start to be a little concerned about the water escaping from the damaged section of the spillway on the dam side. The chances of it eroding all the way to the dam are probably remote, but I would still rather see all of that water escaping out the other side away from the dam.