OPINION: Evan’s Bay is an iconic part of the Wellington harbour “blue belt”.

Stormy days have their own wild beauty, while in sunny times the water is dotted with sails, recreational anglers hang out their lines, and swimmers, cyclists and walkers soak up the warmth and the ambience.

Pods of orcas and other fish cruise up the deep water channel by the Miramar wharf where an airport runway extension is now proposed.

In July 100 residents from the eastern suburbs attended a meeting to express their concern about a proposal that will have a serious impact on one of Wellington’s major natural assets.

The extension into Evans Bay will be both long and wide, as taxi-ing and turn-around space are also required. The height could be 10-12 metres above sea level, and with a water depth of around 17 metres huge quantities of fill will be needed, with consequent damage to the natural environment and fish spawning grounds.

This is not just an issue for the eastern suburbs. It will hit all Wellington ratepayers in the back pocket as they are asked to stump up $200 million (plus interest) of the estimated $300m cost.

But how firm is that estimate? Will it include changes to roading and other infrastructure? What are the cost implications for fuel tanker operations at Burnham wharf, right by the new extension?

The claimed potential benefits from a 2012 Business and Economic Research Limited report (Berl) are optimistic. Increased numbers of tourists are mentioned, for example, but for many overseas visitors Wellington is a “through” city rather than a “to” city.

Visitors largely start and finish their journeys in Auckland, Christchurch or Queenstown. Wellington’s best strategy is to attract tourists to stop and stay longer in Wellington on the way through.

Berl also estimates that foreign student numbers could more than double from the present 4800 to 10,000. This seems a somewhat inflated figure to achieve by eliminating a domestic flight connection. The quality of what’s on offer in the tertiary sector is the critical incentive.

A direct flight to, say, Singapore, could be useful for passengers to Singapore, or in transit to Europe. But for other Asian destinations Singapore would simply replace Auckland or Christchurch as the transfer point.

Given Berl’s optimistic assumptions on passenger numbers, airlines might well be having doubts about load factors, especially if a new service undermined loadings to Auckland or Christchurch. Insufficient passenger numbers doomed the AirAsia X service between Kuala Lumpur and Christchurch.

In terms of aircraft operations, clearing the Newlands hill is already a concern for pilots, and an extended runway would mean heavier planes on a steeper flight path. Just recently 20 passengers had to be offloaded because of light wind conditions. It is entirely possible that advancing aircraft technology will allow larger planes to land on the existing runway without an extension.

Climate change is another challenge. Airlines offering heavily discounted fares tempt customers to take more flights, but in London recently plans to extend Heathrow were abandoned out of concern to reduce carbon emissions.

Of major concern is the question of who pays for the runway extension. Infratil, 67 per cent owner of the airport, aims to return money to shareholders at the rate of 20 per cent after tax (Runway won’t fly without city cash, Aug 15).

Tellingly, it added that it would not contribute more than 33 per cent of the cost ($100 million) because the project does not stack up on a user-pays basis. Instead it is looking to ratepayers or taxpayers to come up with the remaining $200m.

The Government has said it is not a priority for government funding, which leaves Wellington ratepayers exposed to paying the bill.

With only one-third council ownership, citizens are being asked to pay two-thirds of the cost. The Wellington City Council has a poor track record in stewardship of ratepayers’ money, having recently agreed to fund a disproportionate 50 per cent of the $2m resource consent costs.

Adding $200m to the existing city debt of $380m is fiscally irresponsible for a project with very questionable benefits. Mayoral and council candidates are currently making commitments to contain debt levels and rates. Many are also making commitments to social housing, a living wage, improved public transport and earthquake strengthening.

These are issues of greater priority with guaranteed benefits for all Wellingtonians.

Richard Randerson is the chairman of the Guardians of Evans Bay.