Dam Safety
What is a Dam?
A dam, as defined by section 7 of the Building Act 2004:
(a) 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
(b) includes –
- a flood control dam; and
- a natural feature that has been significantly modified to function as a dam; and
- a canal; but
(c) does not include a stopbank designed to control floodwaters.
An appurtenant structure as defined by section 7 of the Building Act 2004, in relation to a dam, means a structure that is integral to the safe functioning of the dam as a structure for retaining water or other fluid.
Overview of Dam Safety Regulations 2022
The Building (Dam Safety) Regulations 2022 were announced by the Ministry of Business, Innovation and Employment (MBIE) in May 2022. The regulations have been made to increase the resilience and safety of Aotearoa/New Zealand’s dams, protecting people, property, and the environment from the potential impacts of dam failures. They also provide a nationally consistent risk-based approach to dam safety. Only dams that meet a certain height and volume threshold are impacted by the regulations and need to be classified.
These regulations come into force on 13 May 2024.
Dams only need to be classified if they are 4 or more metres in height and store 20,000 or more cubic metres volume of water, or other fluid.
Dam Classification Certificate
Dam owners will need to check if their dam meets the classifiable dam threshold. If it does, they will need to carry out a potential impact classification (PIC) to assess the potential impact (i.e. low, medium, or high) their dam’s failure could have on the community, historical or cultural places, critical or major infrastructure, and the natural environment.
Dam owners must provide their dam’s classification certificate (which they will need to get certified by a Recognised Engineer) to Council by 13 August 2024.
Dam owners may have further obligations depending on whether their dam is assessed as low, medium, or high impact. Owners of dams assessed as having a low potential impact will have fewer responsibilities, whereas those with a medium or high potential impact will have more responsibilities.
Dam Safety Assurance Programme
A Dam Safety Assurance Programme (DSAP) is only required for dams with a medium or high PIC.
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.
For a medium PIC dam, the DSAP must be:
- Certified by a recognised engineer and submitted to Council for approval up to two years after the regional authority approves the PIC.
- It must be reviewed within ten years after the date which the regional authority approves the DSAP, and then after the first review, at intervals of not more than seven years.
For a high PIC dam, the DSAP must be:
- Certified by a recognised engineer and submitted to Council for approval up to one year after the regional authority approves the PIC.
- It must be reviewed within five years after the date which the regional authority approves the DSAP, and then after the first review, at intervals of not more than five years.
Annual Dam Compliance Certificate
An annual dam compliance certificate is only required for dams with a medium or high PIC.
On each yearly anniversary of the dams DSAP approval, the dam owner must have a recognised engineer audit evidence of their compliance with the DSAP and prepare an annual dam compliance certificate. Either the owner, or the recognised engineer needs to provide a copy of the certified annual dam compliance certificate to Council.
Changes to the Regulations
On 28 March 2024, the Government changed the height and volume thresholds of a classifiable dam. The regulations will no longer apply to dams that are less than four meters high, regardless of their storage volume. A Classifiable Dam is now defined using a single height and volume threshold of four metres or higher and 20,000 or more cubic metres of stored liquid.
Note: In accordance with the above announcement, the Building (Dam Safety) Regulations 2022, Section 5(1) will be revised in due course to show the amended meaning of a classifiable dam.
Dams Register
In accordance with the Building Act 2004, Marlborough District Council as a regional authority is required to maintain a register of all dams in the Marlborough region. This register enables a better understanding of Marlborough’s dam portfolio and assists Council in providing appropriate support and resources to dam owners, including in emergency situations.
If you own a dam, you should check with Council whether your dam is on the register.
Contact: damsafety@marlborough.govt.nz
