Review of WRC’s policy on dangerous dams, earthquake-prone dams and flood-prone dams

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Proposed policy on dangerous dams, earthquake-prone dams and flood-prone dams

Section 161 of the Building Act 2004 (Act) requires all regional councils to adopt a policy on dangerous dams, earthquake-prone dams and flood-prone dams.

This policy sets out what Waikato Regional Council will do in relation to a dangerous, earthquake-prone or flood-prone dam in the Waikato region. It is a short policy that covers our regulatory and legislative responsibilities in relation to these dams under the Building Act 2004.

The policy has three key sections:

How we will perform our legislative functions in relation to dangerous, earthquake-prone or flood-prone dams.
We have a variety of functions under the Act, and our approach is explained in more detail in the policy. For example, we may put up fencing or hoardings around the dangerous dam to stop people approaching it.
The policy sets out that we will prioritise safety at all times, following a risk-based approach.
When undertaking our functions, we will also protect the health and wellbeing of the environment and have regard to cultural and heritage values.
How the policy will apply to heritage dams.
If a dangerous dam is also a heritage dam, we will account for the need to facilitate the preservation of significant heritage values.

About the proposed update

We are updating our policy so that it aligns with central government’s new dam safety requirements.
Those new requirements include the Building (Dam Safety) Regulations 2022 (Regulations) which come into effect in May 2024. From that date, owners of dams that meet the height and volume requirements will need to confirm the potential risk their dam poses, put in place safety plans and undertake regular dam inspections.
You should read this policy if you have a dam that is a classifiable dam. A classifiable dam (as defined in regulation 5 of the Regulations) is either:
1. 4 metres or more in height and holding 20,000 m3 or more in volume; or
2. 1 metre or more in height and retaining 40,000 m3 or more in volume.
Measures by a regional authority to avoid immediate danger also apply to all other dams.
These terms are defined in the Building Act 2004. The Building Act 2004 states that a dam is dangerous if it is a high potential or medium potential impact dam; and is likely to fail –
1. in the ordinary course of events;
2. or in a moderate earthquake (as defined in the Regulations);
3. or in a moderate flood (as defined in the Regulations).
A dam is an earthquake-prone dam for the purposes of the Act if the dam –
1. is a high potential impact dam or a medium potential impact dam; and
2. is likely to fail in an earthquake threshold event (as defined in the Regulations).
A dam is a flood-prone dam for the purposes of the Act if the dam –
1. is a high potential impact dam or a medium potential impact dam; and
2. is likely to fail in a flood threshold event (as defined in the Regulations).
The policy does not classify dams. The Regulations require dam owners to assess their dam as either low, medium or high potential impact. Their assessment considers the impact to the community, cultural sites, critical and major infrastructure, and the natural environment. If it is a medium or high potential impact dam, the Building Act requires the owner to prepare a dam safety assurance programme.
The council does not undertake this assessment nor is it responsible for preparing the dam safety assurance programme—this is the role of the dam owner and their recognised engineer.
However, the dam owner must immediately notify the council if they believe their dam is dangerous. We will then respond in accordance with the policy.
The policy also does not cover consenting matters under the Resource Management Act 1991, Natural and Built Environment Act 2023 or Building Act 2004.
Submissions should relate to the contents of the policy. The council is not able to change anything in the Act or Regulations.