While important changes to the Building Act Regulations relating to dam safety are due for implementation in May 2024, those who own dams say they are already well aware of their responsibilities. 

In addition, the Otago Regional Council (ORC) is updating its policy on how it deals with dangerous, earthquake-prone, or flood-prone dams in Otago, and how it reviews the policy at regular intervals. 

These changes will be available for public consultation.

The policy, which the council is required to have under the Building Act 2004, is being updated to ensure it is fit for purpose and in line with the nationwide Building (Dam Safety) regulations.

Contact Energy civil dam safety engineer Joe Wheeler said the dam safety regulations apply to all dams greater than 4m high that store more than 20,000m3, which includes the Hawea, Clyde and Roxburgh dams.

The company already has an established comprehensive dam safety programme in place with a dedicated dam safety team.

For Contact, compliance with the new regulations from May 2024 will largely be a matter of preparing existing information in the format required for the regulations, and having this certified by a recognised engineer before submitting it to the ORC.

He said none of Contact’s dams are flood-prone, earthquake-prone or dangerous.

ORC team leader consents Rebecca Jackson is leading this work and said the purpose of the policy is to help prevent the catastrophic failure of a potentially dangerous dam, and to ensure issues in an earthquake-prone or flood-prone dam are addressed.

These new regulations largely relate to dam owner responsibilities, including a requirement for owners to regularly assess and report on the condition of their dam, and to tell potentially affected people if there are any safety risks.

Consultant engineer Peter Mulvihill said while a lot of the region’s older infrastructure such as bridges and dams were built to different standards than exist today, the large majority have performed well.

As part of a risk management process, large dams - especially ones with a Medium of High Potential Impact Classification, are subject to regular checks and performance reviews, he said.

In addition the new regulations will require up to date consequence assessment and ongoing reporting to regional councils, Peter said.

The Omakau Area Irrigation Company owns the 90-year-old Falls Dam and engineers are regularly checking and reporting on its performance.

Director Murray Heckler said monthly reporting of the dam and also after small earthquakes has shown no problems. 

The safety management procedures have been around for some time, “and we are carrying on doing what we have to do to pass those tests, and being responsible.”

Submissions will be open to the public on November 13 and feedback is welcomed on the proposed policy.

In December, the ORC will decide how many hearings are required and their locations and then will consider changes and adopt the new policy.