Intensification of land use, whether for agriculture or housing or industry, is inevitable for one simple reason: every day there are more people who need more food, work, goods and services, and the land we have to provide those is finite.

Indeed, if even the moderate projections for sea-level rise are correct, many parts of lowland New Zealand will soon be swamped; add in global warming and areas like the Manawatu could morph into a chain of tropical islands by century's end.

Which makes planning urban expansion while protecting arable land in Hawke's Bay even more fraught.

But regardless of that added dimension of uncertainty that must be giving planners nightmares, once land is developed, with all the roads footpaths driveways and other impermeable surfaces urbanisation includes, it is lost to agriculture and ruined for any future production.

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When you're dealing with some of the richest most versatile soils on the planet, every hectare is crucial.

And every hectare lost is in effect a crime against the future well-being of our community - a community undergoing a sudden surge in population as Aucklanders and expats flee the big smokes for a less demanding provincial lifestyle.

So it's little wonder the first five-year review of the Heretaunga Urban Development Strategy (HPUDS) is causing headaches for our collective councils.

They are caught between a rock and a hard place: the need for more land for development versus the need to protect the valuable soils surrounding our towns.

This was of course the whole point of HPUDS in the first place - to sort out a 30-40 year strategy to define and achieve both needs. And the plan adopted in 2010 seemed a perfectly reasonable start.

If that plan has come a bit unstuck, it's mainly because the rate of growth has been much higher than anticipated, giving developers and buyers alike little time to get used to the idea of going up instead of out and condensing residential living space.

Perhaps it is also pointing up that the document did not go far enough in allocating future "greenfields" potential, because land the study identified, and is now proposing to add to, merely extends existing urban areas rather than any separate new areas being earmarked for satellite suburbs.

Point being, the land immediately around Hastings is the most valuable in terms of soils, whereas locations like Bridge Pa or the Tukituki valley, or the Taradale or Havelock hills, are of lesser agricultural value.

So why not think longer-term and work on providing entirely new suburbs on "lesser-quality" land? It's not as if these places are more than a quarter-hour's drive from the city - and there's enough variety of landform to keep everyone happy.

One thing is sure: urban creep cannot be left to "the market" to manage.

Those who stand to make money from property development and sales will inevitably opt for the "easy-do" fast-buck approach, and bugger anything else the land might be good (make that, better) for.

Just as it's possible to intensify agriculture without ruining the land, there are many ways to intensify the existing urban zones, some of which reduce development costs.

But a major stumbling block is the lack of carrots and sticks for landowners and developers.

An appropriate scale of reduced fees could encourage intensification, while those wanting a traditional quarter-acre should pay more.

In brief, HPUDS is an excellent initiative, but to date is more an obvious than a comprehensive solution.

As far as greenfields are concerned, councils need to set vested-interests aside, and let the nature of the land dictate the built form, not the other way about.