Overseer protection of our waterways

Overseer report welcome

by Mike Isle

Environment Canterbury has welcomed the Overseer report released on 12 December by the Parliamentary Commissioner for the Environment (PCE).

The Regional Council Uses of Overseer report was completed by the PCE as an independent investigation of the Overseer model, which is used to estimate nitrogen leaching from farmland into freshwater catchment systems.

“We welcome the report, which helps to inform the debate around the role of Overseer both as a method to improve freshwater quality as well as its use as a regulatory tool,” said Environment Canterbury’s director of science, Stefanie Rixecker.

“Of most interest is the recommendations made in the report on how to improve Overseer as a regulatory tool, which is timely and useful.”

The PCE has recommended a comprehensive evaluation of Overseer, including an independent peer review, as well as undertaking a sensitivity and uncertainty analysis. In addition, the report recommends greater transparency on how the Overseer model works, as well as better alignment of the ownership, governance and funding. There may also be a bigger role for central government in providing guidance around how models are used in environmental regulation.

“While we’re aware of the limitations of Overseer as a regulatory tool, we are also encouraged by the culture of continuous improvement around the model to make it more relevant for both farmers and regional councils,” Ms Rixecker said.

“We have been using Overseer for around 10 years. Our latest update to the Canterbury Land and Water Regional Plan, Plan Change 5, eliminates reliance on a fixed Overseer estimate and replaces it with a threshold based on irrigated area or the use of winter grazing of stock. We look forward to continuing our work in the Overseer space.