River health improving — report
Positive water quality trend measured over past decade in majority of streams
River water quality around the country has improved in the past decade and new information shows the majority of our rivers are getting better.
The latest National River Water Quality Trends (2007-2016) data was released by Land, Air, Water Aotearoa (Lawa) yesterday, showing results from regular water quality monitoring carried out over the past 10 years.
The information relates to nearly 1500 freshwater sites that are regularly monitored for water quality by regional or unitary councils. Data is also supplemented by the National Institute of Water and Atmospheric Research.
Ecologist Dr Roger Young, of Cawthron Institute Freshwater Group, said the overall picture was encouraging.
“Looking back from 2016 at a decade of data, for every monitored parameter, more sites showed evi- dence of improving water quality than degrading. My hope is this could represent a turning point in New Zealand’s river health story,” he said.
The national picture showed that in water clarity, ammoniacal nitrogen and total phosphorus concentrations indicated 11, 8 and 16 times more sites with improving trends than degrading trends, respectively.
The report said: “Compared to a previous national water quality trend summary based on data from 2004-2013, the latest results were generally consistent but provide more positive signs relating to water quality improvements.
“Both found more improving trends than degrading trends for total phosphorus, dissolved reactive phos- phorus, E.coli, ammoniacal nitrogen and water clarity.”
The results also indicated improving trends for total oxidised nitrogen and total nitrogen. In the 2004-2013 data, that was the opposite.
The Lawa website provides more detailed information about the health of rivers in 16 regions.
Information is available for rivers in Auckland, Bay of Plenty, Canterbury, Gisborne, Hawkes Bay, Manawatu-Wanganui, Marlborough, Nelson, Northland, Otago, Southland, Taranaki, Tasman, Waikato, Wellington and the West Coast region.
Those navigating the site can click onto a respective region and then click on a specific river or freshwater catchment to see how it fares.
The Auckland region shows results for 36 freshwater catchments in the area; the majority (68 per cent) drain non-forested rural catchments (pastoral farming, horticulture and rural residential), followed by 21 per cent of native forest catchments.
Eight per cent were described as exotic forest and urban catchments.
Dr Young said although the results were positive, water quality was just one indicator of river health and acknowledged that more work can still be done — particularly in those sites that were degrading.
“In order to continue further improvements, we need to invest in freshwater eco-system management, routine monitoring and further research and innovation.”