The scale is deceptive. Take a look at the report on this
https://www.youtube.com/watch?v=5xa_Q1R7mGs&t=132s and you will see a thick concrete spillway with 1.5" rebar. All that was ripped off by the force of the water!
There's probably 20 Hoffman-crew-sized rented vehicles, and subcontracted employees and value-add diesel fuel ain't cheap either. It's going to take probably 9 months, at a minimum.