Desal and the broken windows fallacy

The “broken windows fallacy” is the economic argument that spending money on X is of intrinsic value because of the jobs created, regardless of the value of the thing being done. The reference to broken windows is the argument’s reductio ad absurdum – hire one person to break a bunch of windows, and a second person to fix them. Certainly the people hired to break and fix windows make out OK under the arrangement, but does society benefit?

Supporters of the Carlsbad Desalination Project in California have been making the jobs argument of late:

Like so many San Diegans, David Shin was laid off in 2009.

“I know what it’s about to not be in a job for awhile,” said Shin. “It’s an eye-opener.”

But now, with his gloves on, walking alongside the site for the Carlsbad Desalination Plant, Shin said things are looking up.

“It’s great to know there is work out there,” said Shin. “It not only provides jobs for the local people, but it has the added benefit of clean water for everyone.”

Shin is an engineer who works on the filters that turn ocean water purer than bottled water through reverse osmosis. He’s one of 2,500 San Diegans brought on to work on the controversial plant.

To be clear, I’m not mocking the 10News story I’m quoting there. It at least hints at the flip side of the argument:

Most San Diegans will see a $5 to $7 increase in their residential bill every month.

And of course, the core of the broken windows fallacy is that the money spent building desal plants could have instead been used in some other way. What’s the benefit, and what’s the opportunity cost?

So my question: is coastal desal a broken windows thing?