The Dunedin City Council is warning costs could rise when a new regulatory framework for dam safety is introduced by the Ministry of Business, Innovation and Employment.
MBIE's proposal, first outlined in June, aimed to address the lack of a "consistent and comprehensive'' regulatory framework for monitoring and maintaining the structural integrity of dams.
A council staff report, considered at yesterday's DCC infrastructure services and networks committee meeting, said at present it was the Building Act that outlined the requirements for dam safety in New Zealand.
However, there was a lack of regulation to enforce the requirements, which created risks for people, property and the environment downstream.
Under MBIE's proposed new approach, a new national regulatory framework would reflect both the Building Act and the "industry good practice'' outlined by the New Zealand Dam Safety Guidelines.
The guidelines, which were published by the New Zealand Society on Large Dams, were not at present incorporated into New Zealand law, the report said.
Under the new approach, responsibility for dam safety would remain with dam owners, while regional councils performed the function of dam safety regulator.
But the framework would also spell out the requirements of dam owners, including to assess their dams and - for those deemed large - report on the potential impact of a dam failure.
The council would also have to submit a dam safety assurance programme, certified by an engineer, to be followed in future, and review the documents regularly.
The new approach, if approved, would come into force a year after it was gazetted.
Council policy analyst Scott Campbell, in his report to yesterday's committee meeting, said the council owned nine dams used for raw water storage that would fall under the new approach.
Two of them - Ross Creek and Mt Grand - were deemed to have a "high'' potential impact downstream, should they fail.
The council was working towards full compliance with existing dam safety guidelines but faced "constraints of existing budgets and resourcing'', the report said.
The cost of complying with the extra regulations would be significant and full compliance would increase costs and require additional resource, it said.
Council 3 Waters group manager Tom Dyer said the DCC already assessed its dams for stability and invested in projects such as the Ross Creek update, to ensure any problems were avoided.
Councillors signed off on a submission on the new proposals yesterday, supporting the need for a clear and consistent regulatory approach but suggesting a longer lead-in time, to allow dam owners to plan and budget for the extra requirements.
