Irrigation New Zealand

Submissions close on new regulations on dam safety on 6 August.

We are encouraging affected farmers/ growers to make a submission. These can be emailed to

The consultation document is online here

We have outlined our concerns about the proposals below. We encourage you to include details of your own storage facilities and how you would be affected by the proposal in your submission.

INZ’s general comments on the proposals

We note that any form of storage for water (or other fluids - most likely effluent in our situations) is covered under the definition of “dam.” This includes storage that we would more commonly refer to as: ponds, turkey nests and on plains storage.

Those facilities affected by the proposals are capable of holding:

  • 20,000m3 and 4m or higher or
  • 30,000m3 and are less than 4 high.

Canals are also considered to be dams. It is a matter of considering whether the canal’s stored volume and height exceeds the stated thresholds 20,000m3 and over 4m high or 30,000m3 and any height.

INZ is still gathering data irrigation schemes on the water storage facilities operated by their shareholders..

We have also surveyed affected non-scheme members and we invite non-scheme members with storage to complete this survey if you haven’t already which is online here

Using the information supplied to date as a sample, leads to the conclusion that a substantial majority of irrigation water storage will be affected by the new requirements.

The Building Act already sets many of the principles and definitions used in the new proposals.  These regulations are expected within the wording of the Act.  Therefore, in practical terms, there are quite limited matters that can be challenged in this submission.

INZ’s concerns about the proposals

We have not completed our investigations to begin writing our submission but currently we think the following aspects of the proposed regulations require attention and amendment.

Wide Variety of Dam Types

The language used in the document reflects the situation where dams are built across river/stream beds or in natural valleys. The situation of ponds being formed on plains (at varying slopes) is not well reflected. In particular, the situation where storage ponds have storage below the original ground level is not contemplated.

We intend to submit that the regulations be worded to reflect the fact that it is only the storage volume above original ground level that poses any potential impact.

Size of dam and “Referable Dams”

The Building Act 2004 provides for small/very low potential impact dams to be categorised as “Referable” and assumedly attract a reduced amount of assessment.  In effect this would identify dams that are underneath the “Low Potential Impact” (PIC) category used throughout other parts of the proposed regulations.

However, the proposed regulations seek to do away with the Referable dam category.

Our current thinking is that there may well be a place for the Referable category.  Say in situations where the dam is less than 4m high and is demonstrably situated away from places where people are concentrated and major infrastructure sites.

We are concerned that by removing the referable dam category, small and medium dam and pond owners will be exposed to unjustified compliance costs.

Resource Consent and Building Act requirements

There are examples where dams have required Resource Consents and especially in later times, those consents have conditions that set out matters that are also covered under the Building Act.  In the future more detailed requirements will apply under these regulations. Therefore, it is a concern that dam owners and operators will be required to apply different and potentially conflicting rules under the RMA and the Building Act (including these potentially fairly rule based regulations).

We intend to propose that these regulations set out a process whereby resource consent conditions can be cancelled when their content is covered under the Building Act and these regulations.

Use Recognised Engineer’s Experience

The proposed regulations more closely define the activities and qualifications of the ”Recognised Engineer.” 

This is a term defined in the Building Act that ensures that engineers have specific dam related qualifications and experience. As the regulations are currently proposed, Recognised Engineers have considerable guidance but are still expected to do their Potential Impact Assessments (PIC) using their experience and knowledge. We are concerned that as the submission and drafting process proceeds there will be a tendency to increase the rules that the Recognised Engineers are required to work to. The problem with blanket rules is that they will not neatly fit the full range of situations encountered when evaluating the high number of dams spread throughout NZ.

We intend to support the regulations having outline guidance and rules for the Recognised Engineer and oppose any increase in this regard.

Limited Number of Recognised Engineers

We understand that the number of Recognised Engineers is quite low, and the number of dams has, if anything we think, been under-estimated. We think that having too much work ahead of too few engineers has undesirable effects.

We intend to submit that the implementation phase is longer than the proposed one year. 

We are currently considering some form of coarse impact assessment to get a priority system in place.

Complex Appeal Process

The Building Act requires that Recognised Engineers to approve the Potential Impact Assessment (PIC) and the Dam Safety assurance Programme (DSAP) before these are submitted to the Regional Authority. In the event the Regional Authority does not accept these, there is a complex (and possibly very expensive) process set out that may put undue pressures on the dam owner, who has already retained the Recognised Engineer to undertake the work to a high professional standard.

We intend to submit on this aspect but at this stage have not settled on our suggested solution.