[zhivota]

My immediate thought is at what point does desalination tech + clean energy reach the crossover where building a 60 mile tunnel over 60 years not make sense?

It feels like very soon, and coastal cities can stop relying on hinterland reservoirs for water.

[PLenz]

Probably never. The tunnels cost a lot to build but, once built run almost for free - they're powered by gravity and will keep running for close to a century before major maintained is needed.

[zhivota]

Yeah that makes sense but if growth dictates another tunnel... And it takes another 60 years, your capital expense starts to look a lot like an operating expense. Not to mention one of the big stated purposes of this tunnel is actually to facilitate maintenance of the other tunnels. There is probably more operation cost hidden here than seems obvious.

[margalabargala]

Close to a century?

There are Roman aqueducts in continuous operation for two millenia.

[patmorgan23]

Capital vs operating is a big factor here. The tunnels operations & maintenance cost is probably far lower than a desalinization plant that could produce an equivalent volume of potable water.

[Ericson2314]

Desalination will be a West Coast thing. The East Coast has abundant fresh water.

[youarentrightjr]

> Desalination will be a West Coast thing. The East Coast has abundant fresh water.

It's not entirely accurate to say that the West Coast doesn't have enough fresh water. Oregon and Washington have a lot of rain, and many groundwater resources.

California kneecaps itself with perpetual deeded water rights and mismanagement/closure/lack of improvement to reservoirs and related infrastructure. There's a long history of this kind of stuff in the state (see the watering LA desert, the Salton Sea experiment, and many others).

[mattmaroon]

It’s probably more likely AI will become sentient and kill us than it is desalination and clean energy are cheaper than this.

This was only a 60 year project because of politics.