A need to improve the understanding of how sea-level rise may
affect South Dunedin has led to another monitoring bore being
The Otago Regional Council recently installed a fourth bore
in South Dunedin, complementing three others drilled in 2009.
The bores, drilled to 6m below sea level, were used to
monitor the level of groundwater to see the extent the South
Dunedin coastal aquifer was or could be influenced by
ORC director, engineering, hazards and science, Gavin Palmer
said the extra bore at Culling Park supplemented the earlier
bores so the council could get a better feel for the
distribution of the aquifer throughout the wider South
''We want to get a better understanding of that.''
The need for a fifth bore was being reassessed to ensure the
bores were geographically in the right place.
Unlike other aquifers, South Dunedin's was not used for
irrigation so there had been no need to monitor its levels in
The three earlier bores were drilled in a line from Bathgate
Park to the corner of Victoria Rd and Kennedy St to determine
how far inland the groundwater was influenced by the tides,
A 2012 report on the monitoring results from the 2009 bores
showed the water table height in South Dunedin was very close
to the surface and that it was under the direct influence of
climate and mean sea-level change, plus the drainage provided
by the area's stormwater and wastewater drains.
''Groundwater modelling of this effect suggests that even the
mildest continuation of the current rise of sea-level rise
would create ponding in some parts of the South Dunedin urban
area,'' the report said.
It was hoped the additional bores would help to further
improve the accuracy of the modelling done for that report.