Council spells out the rules on dams
Dam owners were legally responsible for the maintenance and safety of dam works, Marlborough District Council regulatory manager Hans Versteegh said yesterday.
All dams containing more than 20,000 cubic metres of water required building and resource consent and associated operations and management plans, Mr Versteegh said.
Those management plans placed responsibility on the owners for on-going monitoring and maintenance. Under the law, the burden rested with the owners to maintain safety.
Mr Versteegh said building a dam was not just earthworks, it was also building a very big public liability.
There are approximately 150 dams on private land around Marlborough, although most are graded "low impact" in terms of risk. Most dams are in isolated rural areas with a breach path that crosses rural land or runs toward the sea.
The privately-owned Haldon Dam near Seddon was one of very few graded "medium impact".
Dam owners are responsible for notifying police and civil defence should any problem emerge with the security of their dam, Mr Versteegh said.
"If nothing is done to relieve the risk, the council, under the Building Act, has the power to step in and require measures to be taken to avoid immediate danger."
The council had powers to intervene where there was an issue of public safety, he said. The decision to drain the Haldon Dam in Seddon provided a timely reminder to all dam owners that the responsibility for the maintenance and safety of dam works rests with them.
The water level had been lowered by 2.5 metres by yesterday afternoon. Another 1.5m needed to be drained to quake-proof the dam and was expected to be done by tomorrow.
Drainage had slowed when the diggers used to excavate a channel came across sandstone, which was harder to move.
The council owns three dams graded "high impact" - the Taylor Dam and the Barnes and Essons Dams in Picton - and they had a high standard of maintenance and inspection, Mr Versteegh said.
All have been checked since the earthquakes.
Coincidently, the Barnes Dam was empty for annual maintenance at the time of the last earthquake.
It had been checked after the July quake and no damage found.
Since the recent earthquakes, one other dam owner in the Seddon area, in Tallots Road, had contacted the council to get advice.
His dam has since been inspected and found to be secure.
- The Marlborough Express