Photo: 123rf.com
A new project is getting underway to map large parts of New Zealand's coastline in minute detail to help communities mitigate the impacts of climate change and understand New Zealand's ever-changing coastline.
Toitū Te Whenua Land Information New Zealand (LINZ) has selected two suppliers to collect high-definition LiDAR (light detection and ranging) data as part of its 3D Coastal Mapping programme.
Leading the programme for LINZ is Stuart Caie, who said the data would be used to create 3D maps of vulnerable and populated parts of New Zealand's coastline.
"As a small island nation New Zealanders living and working near the coast are exposed to climate events and natural hazards like tsunami, and these will impact valuable infrastructure, environmental and cultural assets close to the sea, as well as coastal biodiversity."
The two companies contracted to collect the LiDAR data were Woolpert NZ for the North Island and NV5 Geospatial for the South Island.
Areas planned to be mapped this summer included coastlines in Gisborne, Bay of Plenty, Taranaki, Manawatū-Whanganui, Hawke's Bay, Wellington, Oamaru, Timaru, Dunedin, Southland, and Westland.
Caie said planes needed to fly about 500 metres above ground when capturing the data, so people might notice when they were in their area.
"Coastal mapping data is used by scientists and environmental planners to better understand how the country may be impacted and help keep communities and infrastructure safe, as well as protect ocean biodiversity through improved habitat mapping."
LINZ's 3D Coastal Mapping programme would create baseline data for up to 40 percent of the coast over the next three years.
The data would be made freely available on the LINZ Data Service website and the LINZ Basemaps service once processed, Caie said.
LiDAR technology determined the shape of the coast and shallow sea floor by sending pulses of light from a sensor fitted in an aircraft that measured the distance to the ground below, building up a 3D picture of the Earth's surface.
"As we've seen with other LiDAR data on land, the coastal data can be used to assess changes to the coast through erosion or subsidence, build-up of dirt and debris from cyclones or weather events, and land uplifting from earthquakes," Caie said.
"We know scientists are excited about this data and the modelling that it can enable, especially as storm surges are likely to become more frequent as sea-level rises in the future."
Caie said to know how much New Zealand would be impacted, LINZ had already begun installing global positioning receivers at sea-level gauges around the coast.
"These sensors measure changes in the vertical movement of the land and coupled with the sea-level gauges will allow us to work out the effect of sea-level rise over time.
"This information will go hand-in-hand with the coastal mapping data for analysis by researchers and planners," he said.
Data would be used to update nautical charts for maritime safety, a core part of LINZ's hydrographic work programme.
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