They probably did, but their options were/are limited. Normally, they would reduce outflows gradually, but when they dropped down to around 30,000, the water falling off the end of the spillway was starting to erode and undermine new ground under the spillway and threatened losing another section of spillway as well as possibly one of the electric transmission towers nearby.
Kind of a "damned if you do, damned if you don't" situation.
They could have alerted land owners what was going on/going to happen. That is not a normal event, so few would have foreseen it, but water experts should have know.
Too bad.
I’ve been following this since the beginning so I know about the spillway damage etc, all due to the dept of water and CA gov idiocy. Human caused disaster.