Comment Desalination plants cost a lot to operate (Score 4, Insightful) 678
And $30B will get you 30 desal plants like Carlsbad's, which cost $1B, and which will provide 7% of what San Diego area residents need.
But the $30B won't get you the power it takes to run them (new power plants?) Or the energy required to power the power plants.
Also, CA's agriculture depends upon cheap water, not expensive desalinated water.
That said, would a $30B pipeline bring in the same amount of water as desal plants? Or more? Operating expenses are sure to be lower, but there'd need to be a detailed economic and engineering case made for one solution over the other.
--PM