The deployment of a new high-tech buoy in Wellington means scientists will no longer have to wait for good weather to check water quality.
Standing at three metres tall and powered by solar panels, the buoy is the most complicated of its kind in New Zealand waters.
It has been put in place southeast of Matiu/Somes Island by NIWA and the regional council to monitor the health of the harbour and check sediment and nutrient-dense plumes coming from the Hutt river following heavy rain.
The buoy is attached to the seafloor, and devices attached at points along its cable means it can simultaneously check river plumes and the effects of waves and currents.
NIWA coastal physicist Joanne O'Callaghan said the buoy's key advantage was its ability to deliver information immediately.
"The buoy makes a phone call to a computer and sends back data of up-to-date conditions in the Harbour," she said.
"This means we don't have to wait for good weather to collect the data, which is never easy in Wellington."
Dr O'Callaghan said plumes that wash into the harbour following heavy rain carry sediments and nutrients with them.
"We have not sampled the harbour routinely before and this will help us learn how much the river influences the harbour waters.
"The plumes last for three to five days but the material is in the system for much longer," she said.
A trial buoy was deployed last September which found water got very fresh after large amounts of rain from storms and cyclones.
Instruments also found tropical cyclones Debbie and Cook led to an algal bloom in the water.
The regional council's coastal scientist Claire Conwell said the buoy would deliver key insights to scientists.
"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."
Dr Conwell said the information will not only be for scientists.
"A key focus for us is to also make the data accessible, so we'll be working with the NIWA team after the buoy is deployed to get the data streaming via our respective websites.
"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."