[thaumaturgy]

Two more issues are water tables (although those have been falling rapidly across much of California over the last few years) and seismic activity -- not just the big quake sort, but also the usual few cm a year of movement in opposite directions sort.

I suspect that this is going to be an engineering project on the scale of the mythical California high-speed rail, and with the same life cycle. PG&E especially has a track record of misusing funds for upgrades and maintenance.