Instead of a big marshy swamp/lake, we now have farmland. Farmland can feed a lot of folks.
And a whole lot less malaria and other swamp/marsh diseases.
What water issues CA has is mostly due to having to feed the bloat that is LA, and aggressively bad management by the water bosses in the state gov.
I think it would be more believable to use a time machine in the storyline than satellites.
Yup. With trickle irrigation, they could have both. If the open trenches carrying water were covered to prevent or greatly reduce evaporative losses, same goes.