john-ston wrote: Future proofing something so we don't end up with a capacity problem ever again is not ludicrously disproportionate.
Ha ha! building all the capacity the city could ever conceivably need until the end of time is very
ludicrously disproportionate, it is economic suicide.
In the case of this sewer we are talking about an extra $20 million that creates the benefit right away. In your dream proposal we are talking about an extra billion at least that will not be of any immediate use. Surely you can see the difference between $20 million and $1,000 million?
One billion dollars spent on infrastructure not being used has a opportunity cost of $60 million a year, i.e. to borrow that money would cost about $60 million a year in interest charges, or if the city had that money in the bank they would lose about $60 million a year in income from interest. If we get zero benefit from infrastructure we don't need then that is $60 million a year (compounding) that is pissed down the drain.
If according to your estimate this 'future proofing' is not used for fifteen years, then by building it fifteen years in advance the compound opportunity cost is equal to $1.4 billion dollars on top of the original opportunity cost of $1 billion.
So to 'future proof' to such a ludicrous and useless degree turns a $1 billion dollar project into a $3.4 billion dollar project, just to get an extra $1 billion worth of benefit that only starts to be used at least fifteen years in the future. Can use see how building an extra tunnel that will sit empty destroys $1.4 billion dollars of wealth?
john-ston wrote:As I said, what would have been the cost of building a surface tunnel to the same specifications?
I've already quoted the cost twice now JJ. The cheapest option was encasement at $26.5 million, versus $47 million for a tunnel.
I should still listen to Doloras.