RM Journal

Regulatory Implications of the Overseer Report – Are Input Controls the Way of the Future?


Author: Lucy de Latour, Partner, Wynn Williams

The use of the Overseer as a tool to estimate nitrogen losses in regulatory frameworks in New Zealand has recently come under the spotlight through a range of reviews.

Questions were initially raised by the Parliamentary Commissioner for the Environment (PCE) review of Overseer in December 2018. The subsequent Scientific Advisory Panel report on Overseer in June 2021 (the Overseer report) raised further questions, leading to a specific response by the Government to the Overseer peer review report released in August 2021.

This article provides an overview of the findings of the Overseer report and the Government’s response. It examines the regulatory implications of the recent reports, both under existing regulatory frameworks, but also looking forward as regional councils move towards giving full effect to the National Policy Statement for Freshwater Management 2020 (NPS-FM).

So, what is Overseer?

Overseer is a model that allows farmers to estimate nutrient loss on their farms (particularly nitrogen). It was originally developed as a tool for farmers wanting to make on-farm decisions that enabled the more efficient use of nutrients (particularly fertilisers). However, with the increasing emphasis under the various iterations of the NPS-FM on limit setting, and managing to limits, reliance on Overseer within regulatory contexts has significantly increased over the last decade or so.

Several regional councils now use it to varying degrees in their regional planning frameworks and as a tool for assessing nitrogen losses from farming activities in resource consenting contexts. A key attraction of a model like Overseer has been the flexibility it gives to farmers, and regulators, compared to other methods of managing the diffuse loss of nitrogen from farmland, such as input controls on stocking rates and fertiliser use.

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