Bruce Bisset: Ruataniwha review - Their guess is as good as mine

Bruce Bisset

In a perfect world, the review of the Ruataniwha water storage scheme (RWSS) tabled this week would clearly indicate one way or another whether it was a good idea. But this is not a perfect world.

Nor is it a perfect review report; by its nature it contains little that is new, and it still doesn't provide surety to many of the obvious questions.

However what it does, clearly, set out is that the RWSS is not a perfect scheme - and that even if it were, now is not the perfect time for it. Because as the review identifies, there are so many unknowns and variable risks, economic and environmental, that it's currently not possible to say whether the scheme would succeed.

Yes, the review baldly states just that.

At which point, if you were a Hawke's Bay regional councillor, would you bet your career and your region's future on a billion dollar project that the best professional advice available cannot assure you will do the job it's designed for?

No, you wouldn't. Not if you had even half a modicum of sense. And certainly not if you wanted to be re-elected.

Bottom line: the RWSS may be a good idea at some point, but that point will not arise until the basic science and technology needed to ensure it performs as it should is in place and working well.

At a guess, judging from the many caveats the review flags, that's at least a decade down the track.

So, either can it or shelve the whole thing until that time comes.

Let's remember it's primarily we ratepayers who will fund the dam, directly including decommissioning it when it's "handed back" in 70 years' time. Though that cost is finally given a figure - $26m to $30m - it's a very off-the-cuff estimate that still isn't included in the overall financial model.

So all the fancy charts modelling this financial return against that uptake of water based on such-and-such landuse are basically skewed, because the decommissioning cost is ignored.

A regional council that's never heard of whole-life accounting, where you include the cost of disposal, not to mention the (also ignored) social and cultural costs? Astounding.

Far more concerning, the report notes it is "highly improbable and may even be physically impossible" to produce a management regime that delivers the environmental outcomes that are the driver behind this scheme's conception.

That is, ensuring phosphorous and nitrogen leaching is controlled within the limits specified in Plan Change 6 for the Tukituki catchment. And that periphyton (algae) growth is diminished and macroinvertebrate health improved against present levels.

Oh, you thought it was all about irrigation?

Or, more broadly, regional economic benefit?

Well, yes, it's about those, too; but a regional council has protection and enhancement of the environment as its core responsibility, and it's that responsibility to ensure the health of the Tukituki River that must be (and supposedly is) the major driver for a council-led scheme like this. Everything else is consequent.

Otherwise, why would the council do it? They wouldn't; they'd leave it up to the farmers who want to irrigate to run up a scheme, and good luck to them.

True, the council has to try to meet the PC6 constraints whether the dam goes ahead or not, but adding to that "improbable" pressure with a complex scheme that will intensify farming in an already-stressed catchment before they understand how to ameliorate the effects is inviting disaster.

This would be a public work that must achieve its public purpose. If the review makes one thing clear, it's that no one knows if it can.

• Bruce Bisset is a freelance writer and poet.