Sea level rise subject of study

A major engineering project designed to protect South Dunedin from rising sea levels will not solve the problems many residents already face.

The council has commissioned consultancy firm Beca to study what options are available to protect the city's most densely populated area from a sea level rise of 0.8m-1.6m over the next 76 years.

Corporate policy team leader Maria Ioannou said they were looking at the area of South Dunedin and the harbour edge through to Forsyth Barr Stadium.

''The science is pretty clear now. There is sea level rise ... even suggesting there is much debate about the science now is kind of false.''

She said Beca had come up with one possible solution that would be presented to the council's planning and regulatory committee on June 3.

''It is not just water coming over ... it is ground water levels coming up, which doesn't really offer up easy engineering solutions.''

Foley Plumbers director Chris Sutherland said it had been common knowledge that the area was tidal. Some streets were worse than others, depending on their elevation.

Plumbers had to be wary of the tide while installing drainage in the South Dunedin area and even inland they could dig a ditch and find it filling with water, Mr Sutherland said.

One of the options engineers were looking at to prevent the problem getting worse in the future was a series of pumps and drains to keep the water table artificially low.

Ms Ioannou said they were not yet considering a ''managed retreat'' of the area, as some other cities around the world were.

She accepted there were already problems across the low-lying areas of South Dunedin but Beca had been asked to come up with a solution that would ''maintain the status quo''.

''It would be no surprise to most people who live in South Dunedin that it is a damp, low-lying part of town. Most people's gardens, you go down about 30cm and you hit water.''

She said other work planned for the area - fixing leaky stormwater pipes - might actually make the problem worse.

''Some of our pipes are very old, so they are quite porous ... so they are acting in some ways as a sort of drainage system.''

She said that was not ideal when it came to treating the wastewater but it was ''kind of good from a soggy ground perspective'' because it might be keeping it drier.

 

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