Buoy fills void in water monitoring
It was a gentle introduction to its new home in Wellington Harbour for a ground-breaking weather and water monitoring buoy off the coast of Matiu/Somes Island.
The 500-kilogram buoy, deployed off the National Institute of Water and Atmospheric Research (Niwa) ship Tangaroa yesterday, will fill a ‘‘massive data gap’’ in measuring water quality, especially following heavy rain which causes flumes to wash into the harbour from the Hutt River.
The calm and sunny conditions which greeted the $350,000 buoy yesterday are sure to be a far cry from some of the weather it will endure off the southeast coast of the island.
The solar-powered buoy, a joint initiative between Niwa and Greater Wellington Regional Council, will measure real-time currents, waves, salinity (salt content), temperature, oxygen, chlorophyll, ocean acidification and wind.
The regional council’s aquatic ecosystems team leader, Dr Megan Oliver, said the buoy would record crucial water quality and weather information.
There were similar buoys in Auckland, Waikato, Tasman and Hawke’s Bay, she said.
‘‘So it’s contributing not only in a regional sense to filling a massive data gap that we have about water quality, and the physical nature of water – how water moves and where it goes – but it will also contribute to a national network of information.’’
The buoy was lowered using a crane, with 1500kg weights dropped about 20 metres below the water surface beforehand.
Niwa coastal physicist Dr Joanne O’Callaghan said the buoy will make phone calls to a computer which will sent information back to the research centre.
‘‘This means we don’t have to wait for good weather to collect the data, which is never easy in Wellington.’’
The three-metre AXYS Technologies buoy, constructed at Greta Point by Niwa’s mooring technician Mike Brewer, is the most complicated of its kind in New Zealand waters.
‘‘We have not sampled the harbour routinely before and this will help us learn how much the river influences the harbour waters,’’ O’Callaghan said.
An instrument just under the water surface will catch river plumes, which are only one or two metres deep.
There is another instrument near the seabed and two more in the water to measure how much waves and currents move sediments during storms.
Dr Claire Conwell, one of the regional council’s coastal scientists, said the buoy deployment would mark the start of a dedicated water quality monitoring programme for Wellington Harbour and the region’s coastal marine area.
‘‘This information will help us to make links between the freshwater and marine environments, and to assess the impacts on water quality of land-based activities.
‘‘In the long run, we’d like to see this sit alongside other data from buoys across New Zealand, forming part of a national network.’’