Dam safety up for discussion
2 June, 2006
Dam safety up for discussion
Building Issues Minister Clayton Cosgrove today released a discussion document looking at safety options for larger dams.
Mr Cosgrove said the importance of dam safety has been highlighted by the breach of the Opuha Dam in 1997 and flood events in the late 1990s and in 2004.
"A formal system of dam monitoring, inspection and maintenance is clearly needed," he said. " Dams sometimes fail, meaning there is potential for loss of life, damage to property and the environment. The proposed measures will ensure dams are well built, that larger dams are regularly monitored, and that potential risks are reduced.”
For a rough guide, a dam will have to have a capacity of about five-to-six Olympic-sized swimming pools and be three or more metres deep, to be covered by the proposed safety scheme. Owners of smaller dams are not affected.
The "Regulations for the
Dam Safety Scheme: Discussion Document" proposes:
- New regulations to establish a dam classification system involving certification by qualified engineers
- The criteria and standards for dam safety assurance programmes
- Definitions of dangerous dams
- The introduction of dam owner accreditation.
Many major dams already have safety management programmes, and these are still relevant. The proposed new scheme pulls all regulatory requirements together. It also recognises that risk factors for a dam can change over time due to factors such as site conditions, hazards such as flood events or earthquakes, and effectiveness of maintenance.
The wide range of stakeholders consulted in developing the proposed new regulations includes regional authorities, the energy industry, professional engineers, dam owners, local government, farming and other rural affairs representatives. Government departments including the Ministry of Agriculture and Forestry, and the Ministry of Civil Defence and Emergency Management, were also consulted.
Mr Cosgrove said all buildings, including dams, must be structurally sound and safe.
"Ensuring dams are well-built and maintained is one of a number of initiatives this Labour-led government is putting in place under the Building Act to transform the building sector. These include the licensing of building practitioners, the accreditation of building consent authorities, the shake-up of the Weathertight Homes Resolution Service, the review of the Building Code and consumer warranties for building work,” Mr Cosgrove said.
Media backgrounder on proposals within the discussion document
- Under the Building Act 2004, a dam is defined as being three or more metres deep and holding a volume of at least 20,000 cubic metres (about the capacity of five-to-six Olympic-sized swimming pools) of any fluid under constant pressure. This will include dams, flood control dams, significantly modified natural features and canals, but exclude stop-banks designed to control floodwaters. Smaller sized dams are not affected by the dam safety scheme. New dams may require a building consent, as they do now.
- The Building Act 2004 requires owners of dams to classify and register any large dam on their property within 3 months of the regulations commencing (likely to be 2007) or when a new dam is built.
- It is proposed that dams will be classified as “low”, “medium” or “high” impact. The different levels of classification refer to the potential impact to the surrounding area and to the people in the area if the dam were to fail or break. The classification must be certified by a recognised engineer. Owners of “medium” or “high” classification dams will need a higher level of certification, monitoring and engineering advice, implemented through new dam safety assurance programmes.
- Once classification is confirmed, the dam will be approved and registered with the relevant regional authority. Regional authorities will compile and maintain a register of dams, and will require annual confirmation that safety assurance programmes are being followed for medium or high classification dams.
- Dam owners with thorough and robust practices and procedures can apply to become accredited dam owners. Accredited dam owners will be exempt from having regional authority approval of classification and safety assurance programmes. This reduces the involvement of regional authorities, and may reduce their overall compliance costs.
- Regional authorities are required to develop policies to identify and mitigate risk from dams considered to be dangerous in the event of a moderate earthquake or moderate flood, as defined in the proposed regulations. This requirement is similar to how territorial authorities (city and district councils) deal with dangerous buildings.
- The cost of compliance for large dam owners will depend on the size, complexity and condition of the dam, and the safety processes already in place.
The government welcomes submissions on how the proposed regulations will impact on dam management and operations. The discussion document Regulations for the Dam Safety Scheme is available from the Department of Building and Housing on www.dbh.govt.nz or by telephoning 0800 242 243. Submissions are open until 31 August 2006. The dam safety scheme is expected to be in place in 2007.