''Water wars'' have broken out in Hawke's Bay in recent years. In 2013 we witnessed the Tractor rallies over water take bans for the Ngaruroro. Debate around the Ruataniwha Water Storage Scheme (aka ''the Dam'') divided the region through much of 2014 to 2016.

In 2017, the degree of concern that emerged within the Hawke's Bay community regarding the proposed Water Conservation Order for the Ngaruroro (WCO) was profound.

The following suggestion may not amount to "peace in our time" but then the historical precedent for such a claim is less than ideal. It would however represent the type of ''region wide approach to resolving our water woes which I advocated in my previous Talking Point (published on December 7, 2017).

In that article I explained my view that water storage will be essential for Hawke's Bay, given how ''fully allocated'' the Ngaruroro catchment seems to be.

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The regional council has already announced it will not allow any more water takes for the Heretaunga Plains aquifer. Climate change aside, the situation can only get more serious with higher minimum flow requirements to protect aquatic habitats in the Ngaruroro clearly in prospect under both TANK and the WCO.

The advantage of the TANK process is that the outcome can incorporate practical solutions to enable our orchardists and crop growers on the plains to survive this prospect. A WCO cannot do that. It is simply regulation, not an integrated solution to the problem.

In my opinion, one of the options on the table in searching for such a solution, should be the Dam. Under this option, a significant volume of water stored within the Dam could be conveyed along the Tukituki River, maintaining higher river flows of benefit to downstream river ecology.

It could then be collected through an intake on the lower river and distributed by pipe or channel system for use within the Heretaunga Plains, as a replacement supply taking pressure off the aquifer and in turn Ngaruroro river.

When I said in my December Talking Point that I could not see a reality for Hawke's Bay without water storage I could have added, "and someone is going to have to pay for it". A key advantage of the Dam in that respect is its scale. Any investigation of options for the Ngaruroro and Heretaunga Plains aquifer will need to confront the further reality that, as to the unit price of water, "bigger is better".

The comprehensive 2017 council-initiated review of the Dam concluded that even medium-sized dams of equivalent total water storage volume could be up to $100 million more expensive.

If, as seems undeniable, there is a need for water storage within this part of Hawke's Bay, an option which can deliver that water at the best price to existing primary industry must surely be worth considering.

That aside, fewer rivers would need to be dammed within Hawke's Bay for the same amount of water stored.

This option could significantly reduce the need to build a large-scale dam (or several medium-sized dams) within either the tributaries or the mainstem reaches of the Ngaruroro, as clearly of concern to the proponents of the WCO, and claimed by them to be of outstanding value.

There are other factors in its favour. The Dam is consented under RMA. It would be years ahead of any other option. Any dam site in the Ngaruroro catchments would present its own geotechnical challenges.

The 2017 review of the Dam referenced an extensive body of expert opinion in concluding it presents no material seismic risk. The substantial resources invested in consenting, reviewing and procuring a construction contract for the Dam would not be wasted.

This option would also have potential to substantially resolve the two fundamental socially and politically driven concerns about the Dam.

One was that it would ultimately be paid for through intensification of farming on the Ruataniwha Plains (including feared expansion into dairy) leading to more nutrient pollution in the Tukituki.

The other was that the Regional Council would in the meantime need to be a cornerstone investor, placing the Port and ratepayer at risk, at least until the point at which all or most of the water from the Dam was sold.

Under the option I am suggesting, the Dam could continue to provide the relief to farmers within Central Hawke's Bay, which they fairly assumed would be in place when the Plan Change 6 minimum flow restrictions came into effect. But instead of all the remaining water stored in the Dam supporting intensification or expansion of farming within the Ruataniwha Plains, a major share of it could be used to serve existing primary industry on the Heretaunga Plains, for which the writing is otherwise seriously on the wall.

In addition, by substantially expanding the ''market'' for water stored behind the Dam to include the Heretaunga Plains, the degree of perceived commercial risk surrounding the project would equally substantially reduce. The council may not need to invest so much capital as an initial cornerstone investor to get the project off the ground, if at all.

When you combine these factors with the proven efficiencies of scale, in my view the Dam emerges as an option which at the very least must be considered.

It provides the potential for a "win-win". It could underpin a regional solution to the incredibly challenging water quantity allocation issues currently facing the council.

What is truly the highest court in the land, Parliament, would need to resolve the land swap issue, as knocked back by the Supreme Court, but in a very different social and environmental context than I have proposed here. I say, that's worth a look.

Martin Williams is a barrister specialising in local government and resource management law, based in Napier.
Views expressed here are the writer's opinion and not the newspaper's. Email: editor@hbtoday.co.nz