Irrigation New Zealand

The Ministry of Business, Innovation, and Employment (MBIE) is consulting on proposed new requirements for owners of dams or storage ponds.

INZ has arranged to meet with officials to discuss the proposal and gather more information about how they could work.  However, our initial take on the proposed regulations is that they include very small ponds that virtually never present a practical risk of flooding events yet could impose significant costs on the owners of dams and storage ponds.

The proposed regulations would apply to:

  • dams or ponds which are less than four metres high and hold 30,000m3 or more, or
  • are four metres or more high and hold 20,000m3 or more.  

This would result in a very large number farm storage ponds being captured by the legislation, even if they are on-plains where any spill would quickly become shallow water.

For owners of dams that meet the above criteria, the minimum they would need to do would be commission a recognised engineer to undertake a Potential Impact Assessment on the dam or pond. This is estimated to cost around $5,000.

If the engineer considered the impact assessment of a dam/pond failure was medium or high then an expensive dam safety assurance programme and annual audit would be required.

The proposed assessment criteria concern us because they appear to result in a bias toward higher potential impact classifications than are practically justified.  This results in substantial costs whereas the expense should, in our view, be focused toward those dams that have significant potential impacts. Even for quite modest sized ponds, the costs of preparing a dam safety assurance programme could range from $6,000 to $30,000 with an annual audit cost of around $5,000.

You can read more about the proposals online at

Consultation closes on 6 August.

We encourage affected dam and pond owners, and irrigation schemes to prepare their own submission also.

Information gathering
INZ is currently working with member schemes to inform our submission by gathering more information on affected dam owners.

We also invite INZ members who are not part of an irrigation scheme to take our short online survey on dams/ ponds to help inform our submission.