Dam Safety Scheme established

On 7 July 2008 the Dam Safety Scheme Regulations were established, bringing in a 24-month transitional period before the scheme comes into force.

New Zealand has about 1150 large dams that, until now, have not been subject to a formal system of dam monitoring, inspection and maintenance. The potential impact of a dam's failure can change over time due to factors such as site conditions, hazards such as flood events or earthquakes, and the effectiveness of maintenance. Accordingly, the Dam Safety Scheme has been introduced to ensure that from 1 July 2010 all large dams are well built, regularly monitored, and the risk to people and property is minimised.

 

Any dam capable of holding 20,000 m³ or more of water or other fluids is affected by the scheme. This is about the capacity of eight Olympic-sized swimming pools, or a rugby field with water 3 m deep, ie, up to the crossbars of the goalposts.

The Dam Safety Scheme requires the owners of a large dam to:

• assess whether their dam is affected by the scheme (ie, meets the size/volume threshold - basically the equivalent of a rugby field filled with water up to the goalposts, see graphic below)
• classify the dam as having low, medium or high potential impact (on people, property and the environment in the downstream area if the dam were to fail)
• get the dam classification certified by a recognised engineer, and
• register the dam and submit its classification with the appropriate regional authority (within three months of the 1 July 2010 commencement date of the scheme or within three months of their dam being commissioned).
• prepare and submit a Dam Safety Assurance Programme (which includes surveillance and maintenance procedures) to the regional authority, within one year if a high potential impact dam, and two years if a medium potential impact category dam
• provide evidence that all procedures in the Dam Safety Assurance Programme have been complied with by submitting an annual Dam Compliance Certificate to the regional authority, and
• ensure the Dam Safety Assurance Programme and annual Dam Compliance Certificate are audited and certified by a recognised engineer.

Regional authorities will compile and maintain a register of dams.

Smaller dams are not affected by the Dam Safety Scheme, although they still need to comply with the Building Act 2004 in terms of meeting Building Code standards, etc.

The Regulations apply to reservoirs of any fluid under constant pressure that has a depth of at least 3 metres and a volume of at least 20,000 cubic metres (about the capacity of eight Olympic-sized swimming pools). This includes dams, flood control dams, significantly modified natural features and canals, but excludes stopbanks designed to control floodwaters.

The Dam Safety Scheme regulations come into force from 1 July 2010, giving dam owners and regional authorities two years to prepare for implementation.

The Department is developing guidance on the scheme which will be available soon at www.dbh.govt.nz