remember the Oroville Dam failures from 2017? Here's a video of how they rebuilt
The Dam has zero operating spillways with 6 months to go until the next potential flooding event and the engineers and construction workers managed to get a one-year temporary in place in time. Then during the wet season, they focused on the emergency spillway which was also damaged, and then went back to finish the main spillway. 2 years to fix a dam with that much damage is seriously impressive.