Sonar survey for Kawau Bay seabed
What lies beneath the waves on the seabed of Kawau Bay hasn’t been seriously looked at in some places, for 50 years.
So a new sonar survey commissioned by Land Information New Zealand (LINZ) and about to get underway, should make the popular boating area safer for folk out on the water.
Not just recording property and roading boundaries LINZ also produce the charts and navigation information to help commercial and recreational craft safely navigate New Zealand waters.
This survey is part of a bigger initiative to get the best information available of the seabed beneath very high marine traffic areas and corridors particularly as the size of commercial ships and recreational craft increases.
This sees parts of the Marlborough Sounds and the approaches to Auckland including the Ta¯ maki Strait getting the once over.
Kawau Bay can already be awash with boats in summer, with the Kawau ferry and watertaxis, sail boats, recreational and commercial fishers.
As Auckland grows the northern coastline is going to come under increasing pressure especially from leisure craft.
While focusing mostly on Kawau Bay the survey will also include some of the Mahurangi Harbour and offshore from Omaha Bay to Leigh.
A part of Kawau Bay was surveyed by the Navy last year but before that the last big survey effort had been done in 1975 with some even earlier in 1964, LINZ spokesman John Summers says.
New sonar technology will be used for these surveys which is capable of picking up features that are less than a metre in size. This ensures any hazards to navigation like uncharted rocks can be identified, Summers says.
But picking up submerged hazards is just one of the uses for the data.
While not the specific focus of the survey, the data is available to research institutes and others to use. This could potentially see it used for environmental management including seabed habitat mapping or modelling the impact of flooding or sea level rise, he says.
The Goat Island marine reserve at Leigh has already been the focus of a similar sea bed survey for the University of Auckland and Waikato University, by Discovery Marine, who have been contracted by LINZ for the Kawau Bay survey work.