Answer to South Dunedin lies far below

SOUTH Dunedin’s future could be determined by what scientists find 70m below the surface.

A drilling programme is being developed by the Otago Regional Council and GNS Science which will help create a more detailed model of how climate change and sea level rise will affect the area.

Two deep bores, one at least 70m, will be drilled to the bedrock so instruments can be installed to continuously monitor the groundwater level.

GNS Science structural geologist Phil Glassey said before any engineering solution could be developed to combat the rising water levels a basic understanding was needed of what was happening below the surface.

Data collected would be used to create an improved threedimensional geological model which would be used by groundwater scientists.

‘‘You really need to have a basic understanding of what is under there, what is the groundwater doing, what are the interactions between sea level and groundwater.’’

The models created would guide the type of infrastructure needed and provide scenarios on what the area may look like in 100 years.

Regional council natural hazards analyst Sharon Hornblow said the drilling was the next stage in the council’s climate change adaptation plan for the South Dunedin.

It would support previous council work monitoring and modelling the groundwater, sea level and coastal land stability in the area, Dr Hornblow said.

Five more holes would be drilled in the central city harbourside area, as it was physically similar to South Dunedin and would face similar challenges, she said.

The drilling would also support the Government’s NZSeaRise Programme which aims at finetuning sea level estimates for New Zealand’s coastline.

Work was likely to start in March or April but the cost of the project was not yet known.

The finished bores would look the same as the regional council’s other monitoring bores in South Dunedin and the effect of drilling on the surrounding area would be minimal, she said.

As well as the regional council and GNS Science, Oceana Gold would support the project, as would the Dunedin City Council.