New tool a game-changer for freshwater management in Auckland

With $452 million of targeted rates earmarked over 10 years to improve water quality, the Auckland Council is making sure it invests in the right solutions and implements regulations that are feasible and practical for everyone.

Developing a framework for informing this decision-making is required of regional authorities through the Government’s National Policy Statement for Freshwater Management.

Rather than reinventing the wheel, Auckland Council took its lead from the United States, where the country’s Environmental Protection Agency (US-EPA) had developed tools to inform its response to the country’s Clean Water Act – with great results.

Over the last 5 years, Auckland Council has built on this international and local expertise to develop its own Freshwater Management Tool (FWMT). But they were careful to tailor it to the specific needs of the Auckland region.

The result is an accounting framework that will help the Council understand and report on water quality in both urban and rural areas. It can also model potential changes, including tracking changes to water quality and quantity from targeted funding, rule-based and voluntary action – from mountain to sea and farm to city.

Weighing up the options

The first of its kind in New Zealand, the FWMT is a valuable action-planning tool. It tests the benefits and costs to landholders, developers and other resource users, of managing water quality limits.

Auckland Council’s scientist Dr Tom Stephens (Principal – Integrated Catchments) says the FWMT tests what’s feasible and helps identify the best mix of actions for the least cost to achieve catchment water quality goals. This includes improving water flow, managing nutrient levels, and minimising sediment, metals and E. coli.

“The FWMT vastly improves our knowledge of water quality, in terms of its current state, the causes of degradation and when it is occurring,” he says.

“We have gone from knowledge of 36 monitored spot-locations to 5,465 modelled catchments. From monitored information once a month, to information about water quality every 15-minutes. From negligible information on contaminant sources, to understanding underlying contributions from 100+ unique urban and rural land uses throughout catchments. It really is a game-changer for water quality science in New Zealand.

“This knowledge is crucial so we can pinpoint where money can be best spent to have the most positive impact. It also informs our regulatory process so we can be confident the resourcing and rules for freshwater management are feasible, fair and targeted to the places and times needed.”

Supporting farmers and growers

The FWMT makes Auckland Council unique in terms of the support it can offer farmers and growers to help achieve the goals in their Freshwater Farm Plans (FW-FP). Tom explains.

“Using information about where, when and why contaminant loss occurs, the FWMT can offer detailed catchment information to farmers, growers and advisors,” he says.

“By modelling possible actions in each catchment to identify the least-cost way to achieve a target, the FWMT can also help advisors and landholders make better decisions on-farm.

“The tool can help identify opportunities on each farm for wetlands, detainment bunds, soil conservation on highly erodible land, riparian management, good farming practices and farm management changes.”

By incorporating actions from a farmer’s FW-FP into the FWMT, improved water quality can be forecast years before it is observed. This gives farmers and growers recognition for the actions they are taking now.

Partnership approach

The development of the FWMT is an iterative process and involves direct engagement and partnership with several leading researchers in the agriculture, engineering, development and tertiary sectors.

Perrin Ag is leading various work projects to help Auckland Council generate information about costs, benefits and opportunities for management practices and mitigation options for the rural sector, including pastoral, horticulture and forestry.

Perrin Ag has provided detailed estimates of mitigation options for horticultural, pastoral and forestry systems in the Auckland region. Specifically, estimates of the life-cycle costs over 50-years on a farm business and estimates of the effectiveness of various farm management mitigations and ‘edge of field’ interventions, such as wetlands, detainment bunds, buffers and erosion space-planting.

Perrin Ag is leading a joint project with HortNZ, Auckland Council, growers and various experts to develop better knowledge of horticultural systems and options to manage water quality. The firm is leading the exercise with growers, HortNZ, the Agribusiness Group, researchers and representatives from Ministry for Environment and Ministry of Primary industries.

The FWMT is supported by ongoing funding from Auckland Council to continuously improve the tool and better support farming, iwi, government and developer decisions.

For more information about this project, email [email protected] or contact Tom Stephens on [email protected] or 021 196 1550.