New Zealand is part-way through an unprecedented attempt to create a management system that will halt the degradation of the clean water we once took for granted.

So far the results have been mixed. The reaching of a consensus on the way forward by 58 interest groups - including iwi, primary industry groups, environmental and recreational organisations - is a major achievement.

But the announcement on May 9 by the Government of a weakened National Policy Statement for freshwater showed the nettle has not yet been firmly grasped.

We consider it our birthright to be able to swim, collect food, and fish in our rivers and lakes. But already many of our lowland rivers are unsafe to drink or swim in, our native freshwater species are in rapid decline and the "100 per cent Pure" branding vital to our tourism and agricultural exports is being questioned overseas.

In Canterbury and some other areas, water is at a premium and as agriculture is intensified demand is putting pressure on the health of groundwater and rivers.

The spread of irrigation is pushing aside native plants and animals in areas such as the Mackenzie Country, where the arid tussock landscape is being invaded by bright green irrigated pasture.

Until recent times, we took our water for granted and assumed it was an infinite resource that did not require careful management. The introduction in 1991 of the Resource Management Act recognised the need to do better.

But intensifying development pressures have since highlighted the need for national consistency and guidance to the regional councils responsible for water management.

This guidance will come from the National Policy Statement which was delivered to the Government by a board of inquiry early last year following public input.

The Government also asked for input from the Land & Water Forum, which brought together the 58 interest groups in 2009.

The forum was asked to collaboratively find a better way to manage water resources and following a year's work, a report was completed last September.

As part of its work, the forum reached a consensus decision that the National Policy Statement should be adopted, with four relatively minor changes.

But the diluted policy statement announced by the Government on May 9 includes more than 20 changes from the board of inquiry version.

Crucially, the statement does not include clear objectives on water quality.

The original board of inquiry version said water quality should at a minimum be maintained, contaminated water should be improved and outstanding fresh water should be protected.

This clearly stated objective provided little opportunity for further water degradation or for expensive and lengthy legal action over its meaning.

The Government's revised statement says the overall quality of water must be maintained or be enhanced, which implies that some water bodies could be degraded provided that others are improved, so the "overall" quality of water in an area is maintained.

This is a disappointing outcome, especially when all the parties in the forum - including the irrigators, the dairy industry, farmers and hydro companies - accepted the board of inquiry water quality objectives.

The result is likely to be huge amounts of time and money wasted in the courts because of the lack of clarity about what "overall" water quality means in each region throughout the country.

Also announced on May 9 was extra money for cleaning up historically contaminated waterways and for developing irrigation and water storage.

While it is obviously desirable to clean up past mistakes, it is important we don't create new ones.

Forest & Bird is concerned about the impact of more irrigation on native animals and plants and the pollution caused by more intensive agriculture.

We urge the Government to adopt the forum's recommendations for genuine co-operation with all of the interested parties in the early stages of planning large scale irrigation and water storage projects.

The Government should also use its proposed investment in storage projects to insist that these incorporate wider environmental and public interests.

A smaller number of large schemes which are designed to minimise environmental and social impacts will be better than - as is mostly the situation now - a large number of badly managed and poorly co-ordinated small schemes.

The forum has been asked to carry on its work, including helping to draw up a set of national environmental standards alongside the National Policy Statement.

These will provide the regional councils with the framework for setting limits and standards on water quality and allocation.

This framework will allow for some regional and catchment variability depending on local conditions.

During this next stage, the forum and the Government will have to work hard to ensure the opportunities missed in the National Policy Statement do not end up costing us the clean water we need and deserve.

Kevin Hackwell is Forest & Bird's advocacy manager.