Dams which meet a certain height and volume threshold defined in Government Regulations, which come into force on 13 May, need to be classified.

The owners of these dams need to arrange and have this classification submitted to ORC no later than 13 August 2024.

ORC’s dam register shows that in Otago 98 dams will be affected by the new regulations, with an extra 34 dams close to exceeding the threshold, requiring further investigation.

Under the new regulations, developed to provide a nationally consistent risk-based approach to dam safety, dams need to be classified if they are 4 metres or more in height and store 20,000 or more cubic metres of water, or other fluid. Dams which are 1 metre or more in height and store 40,000 or more cubic metres volume of water, no longer need to be classified and are not covered by the Regulations.

Actions for dam owners to take

Dam owners will need to check if their dam/s exceed the threshold. If their dam exceeds the threshold, 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.

The regulations allow for anyone to carry out a PIC assessment (e.g. dam owners, farm consultants, technical practitioners). The role of a Recognised Engineer is to audit and certify these PIC assessments. Engineering New Zealand maintains a register of Recognised Engineers that can be accessed on their website.

Dam owners, or Recognised Engineers acting on their behalf, must then provide information about their dam classification (Dam Classification Certificate) to ORC by 13 August 2024.

Additional actions dam owners need to take will then depend on whether their dam is assessed as low, medium or high impact.

ORC’s Acting General Manager Regulatory, Joanna Gilroy, says that ORC’s focus is on the implementation of the regulations and assisting dam owners to understand the steps they need to take over the coming months.

“ORC is here to help as needed with the new regulations and if anyone has any questions they are encouraged to get in touch with the team. We will be contacting dam owners directly, but we also have a number of resources online and are happy to help,” she says.

Support information and resources for dam owners are available on MBIE’s Building Performance website and ORC’s website. Resources include a detailed guidance document and a resource to help dam owners calculate the height and volume of their dam, to see if it is affected by the regulations.

Under the Building Act all Councils are also required to have a policy on how they deal with dangerous, earthquake-prone or flood-prone dams. Otago’s policy is being updated to ensure it is fit for purpose and in line with these new nationwide Building (Dam Safety) regulations. The policy only applies to dams that are believed to be or are dangerous, flood-prone or earthquake-prone under the Building Act.

Information and resources to support dam owners

Ministry of Business, Innovation and Employment (MBIE) Building Performance - Resources webpage

MBIE Building Performance - Managing dams to ensure they are safe webpage

MBIE Building Performance - Measuring and calculating the height and volume of agricultural dams

Engineering New Zealand Te Ao Rangahau - has information on its website about how to find an engineer and/or a Recognised Engineer, and tips on how to effectively engage with them.

ORC - Dam Safety Regulations webpage https://www.orc.govt.nz/damsafety, including the Dam Classification Certificate Form to use for submitting the classification.

A recording of a MBIE webinar for dam owners and other stakeholders who have an interest in dam safety can be found here https://www.building.govt.nz/managing-buildings/dam-safety/resources#:~:text=Available%20resources-,Webinar,-Webinar%20explaining%20the

Where are the affected dams?

Of the 132 confirmed and close to exceeding dams, 82 are in the Central Otago and Queenstown Lakes districts, while 45 are in Dunedin City and Waitaki and Clutha districts.

What type of dams are they?

Our regional dam register indicates that 61 dams are owned by companies and Territorial Authorities (district councils) while 71 dams are owned by private landowners.

What do the new regulations mean? Are these dams unsafe?

Rather than being an assessment of safety, the regulations provide an approach to dam management for large dams that exceed the threshold and don’t imply that large dams are necessarily unsafe. Large dams that exceed the threshold are targeted by the regulations as, in the event that a large dam fails, there is a greater risk of significant impacts to people, property and the environment.

The timeframe for getting this work done is short. Will there be an extension or a grace period?

The Government has imposed the timeframes that compliance is required to be achieved by. At this stage, all dam owners who operate dams that exceed the threshold should focus on completing and supplying a Potential Impact Classification (PIC) assessment that is signed-off by a Recognised Engineer and submitted to ORC on the correct Form by 13 August 2024. ORC does not have the ability to deviate from the requirements imposed under the Government regulations.

Are there enough engineers in Otago to do this work?

It is important to emphasise that a Recognised Engineer is required solely for sign-off of the PIC assessment. They do not have to be based in Otago. Dam owners and engineering practitioners are in the position to gather information, complete any necessary site inspections and any required evaluation and reporting for the Recognised Engineer’s sign-off. Dam owners are encouraged to engage with engineering practitioners and Recognised Engineers as a first step.

Want to know more?

For more information phone our customer services staff on freephone 0800 474 082 or email damsafety@orc.govt.nz

© Scoop Media