Newly released data show that more than 3,500 rivers, lakes, and estuaries across New Zealand are under environmental pressure, with widespread contamination linked to intensive land use.
The Land, Air, Water Aotearoa (LAWA) project released the findings to celebrate World Rivers Day, marking the first opportunity for the public to explore 20 years of freshwater health trends across roughly 1,200 monitored sites.
The data reveal that two-thirds of river sites and half of groundwater bores are affected by E. coli, while two-thirds of lakes are in “poor or very poor condition.”
LAWA chairperson Dr Tim Davie said lakes are especially vulnerable. “Lakes are always going to be under pressure because they hold water for a long time, and pollutants build up,” he said. Speaking beside Canterbury’s Halswell River, Davie acknowledged nitrate issues but noted some improvement. “We’ve got a problem with nitrate in Canterbury and across the country, and there’s a lot of action being taken to improve that.”
Dr Amanda Valois of Greater Wellington said opening the data to the public was a positive step in the Wellington region. “Having this access to knowledge for everybody — not just scientists — is really great,” she said, adding that “a lot of our sites are in poor health.”
“There are positives evident in the data, for example ammonia and dissolved reactive phosphorus have improved at sites where point-source discharges have been upgraded.” Dr Roger Young from the Cawthron Institute said.
“Anywhere where there’s intensive land use, whether that be in a city or intensive agriculture, that has an impact on our waterways.”
The scientists hope the data motivate practical action. “Taking time to give your stream some love is good,” Valois said.