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As lobbyists, they generally push their cases vehemently, apparently willing to give little quarter. On this occasion, however, key environmental groups and rural interests have come together to back the plan.
Neither party will get all they want. That is the nature of compromise. Hopefully, though, specific issues can be worked through, funding found and New Zealand's agricultural production can be increased at the same time as progress is made on ecological restoration and water, landscape and environmental protection.
Encouragingly, all parties have tinged enthusiasm with realistic caution. There is a big difference between a general agreement and its practical application. Everyone knows hard work - and the need for continued flexibility and understanding - remain.
The agreement, piloted by Guy Salmond, has taken two and a-half years to reach. Under it, up to 100,000ha might eventually be set aside for protection in the Mackenzie, Ohau and Omarama Basins in the trade-off for more irrigation and tourism.
It is envisaged almost 10% of the 269,000ha of ''flat and easy country'' will be irrigated, some for sheep and beef and some for cubicle-style dairy farming.
It was this style of agriculture which caused consternation in 2009. The Environmental Defence Society successfully challenged resource consents for cubicle farms for about 17,000 cows.
The proposals smacked of European or North American intensive factory farming and evoked emotive responses. As time had gone on, though, more people are recognising cubicles have distinct advantages in the semi-arid and harsh climate. Cows will be more comfortable and do better if given the option of decent shelter.
Crucially, effluent can be collected and treated much more effectively.
Water quality is perhaps the biggest underlying issue. The massive irrigators and the transformation of paddocks from brown to green has already changed substantial areas around Omarama and other places. But, the run-off from intensive dairying can have serious impact on water - and porous ground creates particular problems.
This, as is acknowledged, remains ''a major outstanding issue'' for the proposed Mackenzie Country Trust to tackle. The trust is also going to have to identify the land to be protected or irrigated. And funding will be a challenge, with up to $3.7 million a year being cited, this having to come from Government, donations or sponsorship.
Interestingly, not all the main irrigators in the basin are among the 22 signatories, although the Environmental Defence Society, Forest and Bird and Fish and Game have signed. Support has come also from local government, Dairy New Zealand and local Federated Farmers.
Defence society chairman Gary Taylor went so far as to say the agreement was ''unique'' in establishing a trust to negotiate joint management agreements with private landowners and high country run-holders to protect significant areas.
Development would still be covered by the Resource Management Act, but - under proposed legislation - applications with trust approval would be more likely to be considered favourably.
Not surprisingly, on the edge of the Southern Alps and with a rugged tawny beauty all its own, tourism is expected to feature more and more in the region's future.
Just as a balance will be essential between farming and environmental protection, tourism will require a balance between attracting crowds and preserving the sense of grandeur and space.
Notable is the backing of the leading statesman of New Zealand conservation, Dunedin-based Sir Alan Mark. He fully supports the agreement, making the points the area is both a unique piece of New Zealand's natural history and an extremely fragile ecosystem. He, like everyone else, must now be hoping the agreement's promise can be fulfilled.
Canterbury-West Coast field officer Jen Miller, meanwhile, said the real test would come during the next phase, when a mechanism was developed to ensure the 100,000ha was protected.
''The hard part will be translating what's been acknowledged by all the parties - that the Mackenzie is far too precious to lose - into reality,'' she said.