ORC has adopted its updated dam policy on how it deals with potentially dangerous, earthquake-prone or flood-prone dams in Otago.

ORC’s Acting General Manager Regulatory, Joanna Gilroy, says the purpose of the updated policy is to continue to have a framework in place to support the reduction of the risk of catastrophic failure from a potentially dangerous dam, earthquake-prone dam or a flood-prone dam where needed.

ORC’s previous policy on dangerous dams was introduced in 2011 and this policy has now been updated to bring it into line with other policies around the country and national legislation.”The ORC policy is required under the Building Act.

“The updated policy only applies to dams which are believed to be, or are, dangerous, flood-prone or earthquake-prone under the Building Act, so it’s highly unlikely to impact on the general public or the majority of dam owners,” she says.

The updated policy was voted for unanimously by ORC’s 12 Councillors last Wednesday at a full council meeting in Dunedin. The policy was publicly notified and went through a full hearing process under the Local Government Act 2002.

Ms Gilroy thanks all the people who made the time and effort to make submissions, between 13 November and 15 December, and attended the subsequent hearings.

“We’re really pleased with the engagement from the community which was very valuable to the hearing panel for the policy,” Ms Gilroy says.

The updated ORC policy is separate to the new national level dam regulations which came into effect earlier this month (explained below) and this week’s ORC adoption was to update to ORC’s existing dam policy.

“The updated policy outlines requirements for dam owners, engineers engaged by owners and for Council. It’s really important that dam owners notify Council if they believe their dam is dangerous, earthquake-prone or flood-prone.”

“This will allow the dam owner and Council to work together to put plans in place to reduce or remove the risk of harm to people, property and the environment in a timely and effective manner,” Ms Gilroy says.

For more information email damsafety@orc.govt.nz or check out Council’s webpage on dams.

The separate, new Government dam regulations

The new Government Regulations on dams came into effect on 13 May, outlining how dams which met a certain height and capacity 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 under the regulations

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.

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