Dam Safety Scheme - Guidance for regional authorities and owners of large dams: Dangerous dams, earthquake-prone dams, floodprone dams and dams posing immediate danger
5.1 Overview of dangerous dams, earthquake-prone dams and flood-prone dams
The Act requires regional authorities to develop a dangerous dams, earthquake-prone dams, and flood-prone dams policy within their region. The purpose of this policy is to help prevent the catastrophic failure of a potentially dangerous dam, and to ensure deficiencies in an earthquake-prone or flood-prone dam are addressed.
Each policy must state the regional authority's approach for fulfilling and prioritising its functions around these types of dams. The policy must also state how it will be applied to heritage dams.
Section 153 of the Act states that a large dam is 'dangerous' for the purposes of the Act if it:
(a) is a high PIC dam or a medium PIC dam; and
- (b) is likely to fail
- (i) in the ordinary course of events; or
- (ii) in a moderate earthquake (as defined in the regulations); or
- (iii) in a moderate flood (as defined in the regulations).
Section 153A of the Act states that a large dam is an earthquake-prone dam if the dam:
(a) is a high PIC dam or medium PIC dam; and
(b) is likely to fail in an earthquake threshold event (as defined in the regulations).
Section 153A of the Act states that a large dam is a flood-prone dam if the dam:
(a) is a high PIC dam or medium PIC dam; and
(b) is likely to fail in a flood threshold event (as defined in the regulations).
Each regional authority is required to have a dangerous dams, earthquake-prone dams and flood-prone dams policy. However, the Department recognises that regional authorities will be unable to finalise their policies until regulations are passed that define what is meant by 'moderate earthquake', 'moderate flood', 'earthquake threshold event' and 'flood threshold event'.
5.2 Functions of a regional authority regarding dangerous dams
Sections 154 to 156 of the Act outline the functions of a regional authority in relation to dangerous dams.
These functions and powers include:
- putting up a hoarding or fence to prevent people from getting too close to the dam
- attaching a notice on or near the dam that warns people not to approach the dam
- requiring work to be carried out on the dam by the owner within a specified period (which must not be less than 10 days), to reduce or remove the danger.
If an owner of a large dam fails to carry out the required work they are liable to a fine of up to $200,000 or an infringement fee of $2000. In addition, the regional authority may apply to a District Court for an order authorising the regional authority to carry out the required building work. The regional authority may then recover the costs of the work from the owner.
If a dam, small or large, is likely to pose immediate danger to the safety of people, property or the environment, the chief executive of a regional authority can issue a warrant under his/her own hand to take action to mitigate the immediate danger posed by the dam and the dam owner will be liable for the costs of the action.
5.3 Functions of a regional authority around earthquake-prone dams and flood-prone dams
Under section 146 (2)(b) of the Act the regional authority may request a large dam owner to review their Dam Safety Assurance Programme if the dam is an earthquake-prone dam or a flood-prone dam.
5.4 Dams posing an immediate danger
Section 157 of the Act outlines what a regional authority can do to remove the danger if it considers a small or large dam poses an immediate danger to the safety of people, property, or the environment.
The chief executive of a regional authority may take any action necessary to remove the immediate danger and later apply to the District Court for a confirmation of warrant for undertaking the appropriate actions. The regional authority may recover the costs for these actions from the dam owner.