Kerikeri River, along the Rainbow Falls track and by the basin at the Stone Store, was noted as being unsuitable for swimming in the report.
Kerikeri River, along the Rainbow Falls track and by the basin at the Stone Store, was noted as being unsuitable for swimming in the report.
The quality of Northland’s rivers and lakes has severely stagnated, with E. coli and sediment the largest problems the region has to overcome.
That’s the verdict from Northland Regional Council (NRC) following a report by the Land, Air, Water Aotearoa (Lawa) project which paints a worrying picture of New Zealand’s1500 river sites and 200 lakes.
The new data, published last week, revealed two-thirds of monitored river sites in Aotearoa graded poorly for harmful E. coli.
There are also troubling trends for our lakes, of which 60 per cent were being plighted by algal and plant growth stemming from nutrient pollution.
“A third of our land is erodible, so we’ve got land that usually washes away during rain. It’s just our geology, really.”
Donaghy said NRC’s science team recently undertook some analysis and “took a range of different parameters and looked at them”.
“What it showed was things aren’t getting worse, but they’re not getting better. That’s what you’ll see in those Lawa results.
“To fix water in some instances, it’s going to take decades … some of this can’t be turned around quickly.
“It’ll take a focused effort over decades - that’s going to make a difference.”
Donaghy said there wasn’t one particular area in Kaipara, Whangārei or the Far North that had better or worse spots than others because “E. coli is spread right down the region”.
“What’s happening on the land is what’s ending up in the river. And it’s not rain washing it in, it’s diffuse.
“Northland has high levels of E.coli in the river networks across the region that appear to be generated from diffuse pollution sources from intensive land uses.”
E. coli is a notorious bacteria linked to animal or human faeces, and is known to cause vomiting, cramping, nausea and diarrhoea.
Charlie’s Rock (pictured), fed by the Waipapa Stream in Kerikeri, was unsuitable for swimming.
The national analysis showed E. coli levels were highest in those river sites surrounded by urban and pastoral land, while sites near native and exotic forest were in better health.
Cawthron Institute freshwater ecosystems manager and scientist with the Lawa project, Dr Roger Young, said the data served as “a valuable prompt to regularly evaluate the health of New Zealand’s awa”.
“A lot of work is under way to improve freshwater. The reports … serve as a reminder of the need for continued attention and action.
“We know that indicators of ecological health take some time to respond to restoration efforts, while some indicators of river water quality can respond more quickly to change.”
In Northland, Donaghy said improvements could be made by planting more trees, and creating wetlands and retention buns which captured sediment as it’s running along the land.
NRC natural resources monitoring manager Jason Donaghy said one third of Northland’s lakes have a low score for water quality.
But change would take time, he said.
“For instance, if you fence off a stream and plant with riparian planting, you may see E. coli levels shift down in five to 10 years’ time.
“But if you’ve got sediment in catchments, that could take decades to fix.”
A search on Lawa’s website on Monday showed several popular spots in Northland had been deemed unsuitable for swimming because water quality didn’t meet national guidelines and there was a high risk of illness.
Charlie’s Rock, fed by the Waipapa stream in Kerikeri, was unsuitable for swimming, as was the Kerikeri river along the Rainbow Falls track and by the basin at the Stone Store.
Tauranga Stream at Tauranga Bay, the Mangakahia River swimming hole and a few spots along the Tūtūkākā Coast, including Wellington’s Bay and Ngunguru Estuary, were all deemed unsafe for swimming last Monday.
Water quality was good, with “excellent water clarity and low nutrient levels”, in the upper catchment of the Awanui River. However, the lower site in the catchment was “degraded with elevated turbidity and nutrient levels”.
Jenny Ling is a news reporter and features writer for the Northern Advocate. She has a special interest in covering health, food, lifestyle, business and animal welfare issues.
