Overseer and regulatory oversight: Models, uncertainty and cleaning up our waterways
Water quality is a serious environmental issue in Aotearoa New Zealand, and nutrient losses from farms have an impact on our rivers, lakes and estuaries. As the country looks to improve the state of its waterways, an important part of the regulatory puzzle is how we measure and place limits on sources of pollution.
Overseer is currently the most commonly used model for calculating nutrient losses in New Zealand. It is used by farmers to improve nutrient use on farms, and more contentiously by regional councils to help inform regulations around water quality.
The Commissioner considered that an independent investigation of this model could help inform the debate around its role in improving water quality, and identify how Overseer can be improved to be better suited for use as a regulatory tool.
A little over a year on from the publication of the report, the Commissioner has written a follow-up letter to government ministers. It provides an assessment of the progress that has been made to date, and offers suggestions on how the report's recommendations might best be carried forward.