Hydrographic survey begins in New Zealand’s Bay of Plenty
A hydrographic survey to map the seafloor in New Zealand’s Bay of Plenty commenced this month, with the collected data aimed at improving navigation safety for ports and wharves. The Bay of Plenty, a large bight along the northern coast of New Zealand’s North Island, is a critical area for maritime activity.
Toitū Te Whenua Land Information New Zealand (LINZ) oversees the surveying of New Zealand’s waters and the updating of nautical charts to enhance maritime safety. According to senior hydrographic surveyor Annette Wilkinson, the survey in the Bay of Plenty will be conducted in two stages by contractors DML Surveys.
Wilkinson explained that the MV Tranquil Image will begin offshore charting near Tauranga and Whakatāne. “The MV Tranquil Image will begin charting back and forth offshore Tauranga and Whakatāne. Locals may notice this survey boat, which can survey 24 hours a day,” she noted.
Shipwrecks and undersea mounds
The survey utilizes multibeam echosounders mounted on the vessel to create detailed 3D images of the seafloor. These high-resolution models reveal underwater features such as shipwrecks and undersea mounds. Wilkinson added that the survey will explore various hazards on the seafloor. “The survey will investigate a number of wrecks, rocks and other natural features on the seafloor that pose a threat to navigation,” she said.
In early 2025, a smaller vessel, the Tupaia, will map the shallower waters around Ōpōtiki as part of the second stage. Wilkinson emphasized the importance of updating nautical charts for all mariners: “Every area of New Zealand waters we survey updates nautical charts to help ensure Kiwis, shipping companies and other mariners have the latest information to safely navigate our waters.”
Once processed next year, 3D models of the collected data will be made freely available on the LINZ Data Service. This survey will complement previous bathymetric data collected in the Bay of Plenty, including coastal zone data from a technical trial earlier this year. Wilkinson noted: “The survey is filling in data gaps, contributing to a higher-definition picture of the areas we know mariners are navigating.”
Beyond navigation, the data has significant potential for scientific applications. Researchers and planners can use the models for tsunami modelling, marine resource management and understanding the composition and structure of the seafloor. Wilkinson highlighted its broader relevance, stating: “This data will also help us understand the shape and type of the seafloor, which is really useful for researchers and planners.”
