Seabed mapping for safer navigation underway in Otago

A hydrographic survey of the seafloor along the coast of Otago is underway to help support safe navigation.

The survey is being conducted by Toitū Te Whenua Land Information New Zealand (LINZ), which is responsible for surveying the waters around New Zealand and updating nautical charts to help keep people safe at sea.

LINZ Senior Hydrographic Surveyor Bradley Cooper says the Otago survey areas include Blueskin Bay, Heyward Point, Taiaroa Head and Cape Saunders. This area was last surveyed in the 1950s and 1980s, and is the first time with modern equipment collecting high resolution data.

The survey may identify previously unknown features like reefs, shoals and wrecks, and will recheck the depths of known objects.

Cooper says the survey will use multi-beam echosounders mounted on a boat that slowly criss-crosses an area to build detailed 3D images of the seafloor. Echosounders send out a fan of sound waves that bounce off the seabed, which builds a 3D picture of the seafloor and anything on it like shipwrecks and undersea mounds.

“Every area of New Zealand waters we survey helps ensure Kiwis and shipping companies have the latest information to safely navigate our waters,” says Cooper.

There is an opportunity for the public to find out more about this exciting survey.

“Locals will be able to see the vessel charting back and forth off the coast and we are also giving the public the opportunity to virtually step aboard the boat and learn more about the survey during a free seminar on 18 July.”

University of Otago School of Surveying is hosting the seminar and people can attend or join remotely to find out more about hydrographic surveying in New Zealand.

“As part of the seminar we’ll be dialling in to the boat while it’s out on the water so attendees will be able to get up close and personal with the survey action,” says Cooper.

The data collected during this survey will assist in planning for natural events like tsunami, marine resource management and for scientific research.

“This data will also help us understand the shape and type of the seafloor, which is really useful for researchers and planners.”

The survey, which is being carried out by Ocean Infinity on behalf of LINZ, is expected to be completed by the end of the month.

The 3D models will be published on the LINZ Data Service  and updated nautical charts will be available from the free NZ Electronic Navigational Chart Service before the end of 2025.

The public can attend the University of Otago School of Surveying seminar in person or on Zoom.

When: 

Thursday 18 July, 12:00 noon

Where: 

• In-person: L1 (room 113, first floor) School of Surveying.
• Online: https://otago.zoom.us/ (ID: 979 1434 6880, P/W: 310310).

View details of all School of Surveying seminars.