After months as a state secret, Tamworth mayor Russell Webb blurted out the cost of the scheme at a press conference last month, before the state and federal governments confirmed the final eye-watering, gut-busting $1.28 billion price tag. It was initially costed for just $484 million.

Unless I am very much mistaken, the 22 gigalitre dam would be the most expensive project in the history of Tamworth. It dwarfs the $53 million augmentation of the Chaffey dam by so much you can't graph it.

Make no mistake: a billion-and-a-bit is a seriously large amount of money.

Let me give you some context.

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Instead of the dam we could buy:

Almost an entire new Canberra-class landing helicopter dock ($1.5 billion). Displacing 27,500 tonnes of water, HMAS Canberra and Adelaide are the largest ships ever commissioned for the Royal Australian Navy. HMAS Tamworth could carry 12 F-35 fighter-bombers, or 18 helicopters, an infantry battalion, and a floating hospital.

At $800 million per boat, Tamworth could commission itself an entire Collins-class submarine and still have the better part of half a billion left over, though we would need some water for it to swim in.

We could buy almost Australia's entire new fleet of 160 M1A1 Abrams main battle tanks ($1.685 billion per). The cavalcade at the country music festival would never be the same again.

More seriously, the city could fund upgrades to virtually every public building, hire scores of new nurses and doctors and have millions left over for cops, teachers, road and rail upgrades and thousands of new housing units.

Dungowan Dam is the equivalent of six upgrades of the Tamworth hospital ($211 million and completed in 2017).

For the price of the dam, we could finance 50 per cent of the total annual budget for Hunter New England Health ($2.5 billion) including services in Newcastle's huge John Hunter Hospital.

We could hire 13,135 years' worth of local cops. Or 15,871 graduate teachers for one year. We could fund Tamworth Regional Council's entire budget of $251 million, rate free, for nearly five years. We could end homelessness in Tamworth by building 4000 social housing units and renting them at mate's rates.

None of these cops, teachers, nurses or council workers are going to make a whit of difference if we run out of water, of course.

In 2019 and 2020, Tamworth really did nearly run dry. We really do need a solution for our long-term water security problems. But compare Dungowan with the augmentation of Chaffey Dam, finished in 2016. Where the earlier project meant 37 gigalitres of storage for the city, the new Dungowan is adding just 15.7 gigalitres to the existing 6.3 gigilitre bucket of water in the current dam.

Assuming no additional budget blowouts, Dungowan's upgrade will cost $76 million per new gigalitre. Chaffey's cost $1.4 million per gigalitre.

In fairness, the project will be the first dam completion in NSW in three decades. Many assume much of the cost actually won't go to concrete at all, reflecting environmental offsets the government must purchase to compensate for the enormous environmental cost of this project (we don't know that this is true though). Perhaps the reason it's expensive is because dams are and that's just life.

But that raises another question: are dams the answer?

Despite the enormous cost and modest benefits of Dungowan, my personal view is that the dam is probably still a good idea. The kicker for me is that the old dam is unsafe and needs to be replaced no matter what. If the state and federal government don't do that, the ratepayer will need to. As a homeowner, I'd much rather pay for the repair through my taxes, not my rates.

But. Half of the city's water is used by industries like the abattoirs. Tamworth council and the CSIRO could fund an entire reverse osmosis wastewater treatment system at the Westdale Water Treatment Plant for less than $100 million. The plant could save as much as 90 per cent of the water used in Tamworth in a given year; far more than any dam, by definition. It is currently not funded by the federal government.

In my opinion, the two projects go together. If we do just the dam and don't do recycling, we've left the problem half-solved and blown the budget for a generation.

Look on the bright side. If the dam project turns out to be the world's biggest, most expensive hole in the ground, for $1.3 billion, Tamworth could buy 20 tonnes of gold, enough to build a solid gold statue 12 metres tall to remind us never to do it again.

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