Overseer in fresh water management 

Overseer is the only tool available in New Zealand capable of predicting annual average nutrient losses from farms.
Because it uses readily available and auditable information, Overseer is being used by some Regional Councils to inform fresh water regulation as part of the government’s National Policy Statement for Freshwater Management.
It does not model the flow of pathogens present in farm animal excrement - only the flow of nutrients introduced by animal dung and urine.

Overseer's role in a low emissions economy

Agricultural greenhouse gas emissions are not yet regulated in New Zealand, however there is a strong national commitment to reduce our climate impact and growing interest in monitoring emissions from the sector.
Overseer estimates methane, nitrous oxide and carbon dioxide emissions at a farm level, and produces a product footprint for the farm. Overseer includes most mitigation options for reducing GHG from agriculture.
We are working closely with scientists and across the sector to continue to improve model so it can support the sector should further monitoring requirements come in to play.

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Challenges for using Overseer in regulation 

Like all models used in regulation, there are challenges in incorporating Overseer outputs into regulatory processes. Modelled information needs to be applied appropriately, according to the strengths and limitations of the model. For policy makers looking to use Overseer, challenges can include:

  • Understanding the model averaging methods.
  • Understanding the level of uncertainty in the modelled outputs.
  • How to deal with changes and updates to the model.
  • Managing input data quality and auditing.
  • Generation of large numbers of consistent and high quality budgets.

Guidance on the use of Overseer in fresh water regulation

In response to the above challenges, regional councils, central government, Overseer Limited and industry have collaborated to create guidance on the use of Overseer in fresh water regulation.

This has included:

  1. A plain English description of Overseer for a non-technical audience –
  2. A stocktake on current use of Overseer by regional councils.
  3. Detailed technical considerations on the use of Overseer by regional councils.

In addition to this project, we commissioned an independent report into using Overseer in freshwater policy.