Tool boosts efforts to improve water quality

Last Updated : 20 May 2022
Auckland Council 's new Freshwater Management Tool will help test the benefits and costs of moves to improve water quality . It is expected to be widely used in both agriculture and horticulture.

With $452 million of targeted rates earmarked over 10 years to improve water quality, Auckland Council is making sure it invests in the right solutions.

The government’s National Policy Statement for Freshwater Management means councils must develop frameworks for informing decision-making.

In a New Zealand first, Auckland Council has taken its lead from the US Environmental Protection Agency, which has developed tools around America’s Clean Water Act, to tailor its own Freshwater Management Tool to Auckland.

That helps us to report on urban and rural water quality, track changes from targeted funding, and rule-based and voluntary actions, and test the benefits and costs of managing water quality limits.

Auckland Council scientist Dr Tom Stephens says the tool helps identify the best mix for the least cost to achieve water goals, such as improving flow, managing nutrient levels, and minimising other contamination.

“It improves our knowledge of our water’s current state, and the causes and timing of degradation.

“We’ve gone from 36 monitored spots to 5465 modelled catchments, monthly information to every 15 minutes, and from limited contamination information to understanding underlying contributors from more than 100 urban and rural land uses. It’s a game-changer.”

He says that information helps pinpoint where money can be best spent and informs regulatory processes so resourcing and freshwater management rules are fair and well-targeted.

The tool is expected to have significant benefits in rural areas such as Rodney, where agriculture is concentrated.

The tool is expected to have significant benefits in rural areas such as Rodney, where agriculture is concentrated.

The tool makes council unique in terms of the support it can offer farmers and growers to achieve the goals in their Freshwater Farm Plans (FW-FP), Stephens says.

“By modelling actions in each catchment, the tool can help landholders make better on-farm decisions by helping identify opportunities for wetlands, detainment bunds, soil conservation, riparian management and farm management changes.”

By incorporating actions from a farmer’s plan into the tool, improved water quality can be forecast years before it is observed, giving farmers and growers recognition for their actions now.

Perrin Ag itself is leading a project for Auckland Council with HortNZ, government ministries, Council, growers and other experts to develop better knowledge of horticultural systems and water quality management options.

Read more here, or email or To find out more about Perrin Ag, click here.


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