Complying with the regulations

Last updated: 13 May 2022

Dam safety timeframes

The regulations require dam owners to take certain actions.

Step 1: Owners of water retention structures to determine if they have a dam

Owners of water retention structures must determine if their structure meets the definition of a dam.

A dam:

  1. means an artificial barrier, and its appurtenant structures that:
    • is constructed to hold back water or other fluid under constant pressure so as to form a reservoir; and
    • is used for the storage, control, or diversion of water or other fluid; and
  2. includes:
    • a flood control dam; and
    • a natural feature that has been significantly modified to function as a dam; and
    • a canal; but
  3. does not include a stopbank designed to control floodwaters.

Read the definition of a dam in section 7 of the Building Act 2004 - legislation.govt.nz

If a water retention structure does not meet this definition, then it is not impacted by the regulations and no further action is required.

If a water retention structure meets this definition, see step 2.

Step 2: Dam owners to determine if they have a classifiable dam

Whether a dam is classifiable depends on its height and the volume of water, or other fluid, it can store above natural ground level.

If a dam meets the height and volume of water, or other fluid, described below, it is a classifiable dam:

  • 4 or more metres and stores 20,000 or more cubic metres volume of water, or other fluid; or
  • 1 or more metres and stores 40,000 or more cubic metres volume of water, or other fluid.

Small dams are excluded from the regulations. This includes small 'turkey nest' dams, irrigation races, stock drinking ponds and weirs.

If a dam is not classifiable, this means it is not impacted by the regulations and no further action is required by dam owners.

If a dam is classifiable, there are certain actions that dam owners must take to ensure their dams are, and remain, safe. See step 3.

Find out about how to measure a dam in the Dam Safety Guidance [PDF 5MB]

Step 3: Dam owners to determine the potential impact classification of their dam

Dam owners with a classifiable dam must assess the potential impact their dam’s failure could have on the community, historical or cultural places, critical or major infrastructure, and the natural environment.

This assessment will determine the dam's potential impact classification (PIC) which will be either low, medium, or high.

Dam owners can determine their dam's PIC themselves, or they can arrange for a technical practitioner to do it on their behalf.

Find out more about how to determine a dam's PIC in the Dam Safety Guidance [PDF 5MB]

Step 3a: Have the PIC audited and certified by a recognised engineer

Once the PIC of a dam has been determined, it needs to be submitted it to a recognised engineer for audit and certification.

The recognised engineer will work with the dam owner to complete a dam classification certificate. The certificate contains:

  • information about the dam
  • the PIC given to the dam
  • information about the dam owner
  • certificate of the recognised engineer.

Download the dam classification certificate [PDF 89KB]

Find a recognised engineer in your area - engineeringnz.org

Step 3b: Submit the PIC to the appropriate regional authority

Once the PIC has been audited and certified by a recognised engineer, a dam owner must provide the dam's classification certificate to the regional authority in whose region the dam is situated, for their approval.

The dam's PIC must be submitted to the regional authority no later than 3 months after regulations commence, or no later than 3 months after the dam is commissioned, whichever is later.

Step 4: Prepare a dam safety assurance programme

A dam safety assurance programme (DSAP) is only required for dams with a medium or high PIC. Dams with a low PIC do not require a DSAP.

The DSAP provides dam owners with a structured framework of plans and procedures to plan and complete the activities required for the safe operation and management of their dams.

Dam owners can prepare the DSAP themselves, or they can arrange for a technical practitioner to prepare it.

The DSAP should be appropriate to the nature of the dam, including the design and construction type of the dam, its potential failure modes, its potential and confirmed dam safety deficiencies, as well as its potential impact classification. 

Find out what information must be included in the Dam Safety Guidance [PDF 5MB]

There are 7 DSAP elements, but only intermediate dam safety reviews and comprehensive dam safety reviews have timeframes within which they must be completed as per the regulations. For this reason, a short summary of these reviews is provided below.

Carry out an intermediate dam safety review

As part of the DSAP, dam owners must prepare and carry out an intermediate dam safety review.

This review is to evaluate dam performance for the loading conditions experienced during the relevant period. It must also identify any dam safety issues.

This review must be carried out every 12 months, with the interval between reviews not exceeding 15 months.

Learn how to carry out an intermediate dam safety review in the Dam Safety Guidance [PDF 5MB]

Carry out a comprehensive dam safety review

As part of the DSAP, dam owners must prepare and carry out a comprehensive dam safety review.

This is a review of the design, construction, operation and performance of a dam, and all systems and procedures that affect dam and reservoir safety, against current dam safety guidelines, standards, and industry practice. It must also identify any dam safety issues and comment on the resolution of past issues.

This review must be carried out every 5 years, with the interval between reviews not exceeding 66 months.

Learn how to carry out a comprehensive dam safety review in the Dam Safety Guidance [PDF 5MB]

Step 4a: Have the DSAP certified by a recognised engineer

Once the DSAP has been prepared, it must be certified by a recognised engineer. The recognised engineer will work with the dam owner to prepare and certify the DSAP form.

The DSAP form contains:

  • the DSAP, attached documents, and any other referenced documents
  • information about the dam
  • the PIC given to the dam
  • information about the dam owner
  • a summary of compliance with criteria and standards
  • documentation of the DSAP
  • a list of appurtenant structures
  • certificate of the recognised engineer.

Download the DSAP form [PDF 85KB]

Find a recognised engineer in your area - engineeringnz.org

Step 4b: Submit the DSAP to the appropriate regional authority

Once the DSAP form has been prepared and certified by a recognised engineer, it must be sent to the regional authority for their approval.

For dams with a medium PIC, the DSAP form must be submitted up to 2 years after the regional authority approves the PIC. For dams with a high PIC, it must be submitted up to 12 months after the regional authority approves the PIC.

Dam owners should ensure that the procedures outlined in the DSAP are followed to ensure the dam is operated, maintained and managed safely. Certain minor items of non-compliance may be acceptable. 

Find out more about submitting the DSAP to the regional authority in the Dam Safety Guidance [PDF 5MB]

Step 5: Prepare an annual dam compliance certificate

Every 12-month anniversary of a dam owner's DSAP approval date, dam owners must have a recognised engineer audit evidence of their compliance with the DSAP and prepare an annual dam compliance certificate.

The certificate contains:

  • the dams name and relevant regional authority
  • the PIC given to the dam
  • approval of the DSAP
  • information about the dam owner
  • compliance information
  • certificate of the recognised engineer.

Download the annual dam compliance certificate [PDF 92 KB]

Step 5a: Have the dam compliance certificate certified by a recognised engineer

Once the dam compliance certificate is prepared, it must be certified by a recognised engineer.

The recognised engineer must audit the dam owner's reports, records and other documents relating to completion of the procedures in the DSAP. They must also certify that the dam owner has complied with the DSAP during the previous 12 months, using the dam compliance certificate.

Step 5b: Supply the dam compliance certificate to the regional authority

Once the dam compliance certificate has been certified by the recognised engineer, it must be supplied to the regional authority. It must be supplied on each anniversary of the DSAP approval.

Step 6: Review the PIC

Dam owners must review their dam's PIC within 5 years of the regional authority approving it. After the first review, it must then be reviewed at intervals of not more than 5 years.

There are other times when a dam's PIC needs to be reviewed.

Find out about other times a dam's PIC needs to be reviewed in the Dam Safety Guidance [PDF 5MB]

Step 7: Review the DSAP

The contents of the DSAP must be reviewed to make sure they are still appropriate, or whether any updates may be required because of any changes to the dam or its PIC.

Owners of a medium PIC dam must review their dam's DSAP within 10 years of the regional authority approving it, and then after the first review, at intervals of not more than 7 years.

Owners of a high PIC dam must review their dam's DSAP within 5 years of the regional authority approving it, and then after the first review, at intervals of not more than 5 years.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: