The Ohinemuri River turned bright orange last week. Photo: The Valley Profile/Davidda Hikatangata
Questions are being raised about whether budget cuts at the Department of Conservation will lead to more contamination events, after a historic mine shaft on Crown land turned a Waikato river bright orange.
On Friday, sediment was discharged from a mine shaft in the Karangahake Gorge, contaminating the Ohinemuri River. Elevated arsenic levels have now been found in the water.
The sediment involved came from a mine entrance associated with the Comstock Low Level Drive, an exploratory mine started in 1896 which never proved profitable. Mining at the drive site stopped in the early 1900s.
DOC is responsible for managing potentially contaminated sites on public conservation land. However, it had its budget for that programme halved from $4 million to $2 million each year over four years in the 2024 budget.
In a budget overview statement on the DOC website on 30 May, the department said the cut "means that setting up the Contaminated Sites Programme will be slowed down".
Forest and Bird Waikato regional conservation manager Dr Kate James said Karangahake Gorge was riddled with mine sites and DOC did not have enough money anymore to deal with the risk.
"I think the cuts to DOC's budget this year for managing old mines, like this contaminated site, is unacceptable."
DOC's acting operations director for the eastern North Island Zane Jensen said DOC was committed to the investigation and ongoing management or remediation of contaminated land sites that may pose risks to human or environmental health and to meeting regulatory obligations.
But that was only happening in certain locations.
Waikato Regional Council staff carry out testing near the river. Photo: Supplied / Waikato Regional Council
Ohinemuri River is in the Karangahake Gorge, and Jensen said as this was a popular recreation area, some old mining sites were actively managed by DOC to ensure they were safe for visitors.
"However, in the wider Karangahake area there are hundreds of other remnants of the mining industry: these are not promoted, not easily accessible and - most crucially - they are not safe for people to enter."
Both Waikato Regional Council and DOC said it was clear that people were entering old mine sites in the area.
"We take a dim view of this sort of activity and do not condone it. It is not safe," Jensen said.
DOC's director of asset management Shan Baththana said the department took a systematic, risk-based approach to how it was addressing all contaminated sites nationally. Comstock Low Level Drive was currently not a focus.
James said this was a problem.
The sediment came from a historic mine in the gorge. Photo: Supplied / Waikato Regional Council
"It does have a huge amount of public visitation and use, swimming and fishing, it is important, it is high risk."
Conservation Minister Tama Potaka said the government was concerned about contamination events, but it was a matter of priorities.
"It is something that is deeply concerning, it is something we have to continue to manage, but we have priorities in the conservation portfolio, when you are looking after so much land - 30 percent of the land in the country and you are only generating about $50 million of revenue - that is something we have to concern ourselves with."
Labour's Conservation spokesperson, Priyanca Radhakrishnan, said cutting the contaminated sites budget was another example of the government taking the country backwards.
She says Labour set up the project to protect people and the environment.
"The whole point was to clean it up and to protect the health of people who live around those sites. So slashing that budget, cutting $8 million from that particular programme, is incredibly reckless and irresponsible," she said.
Meanwhile, Waikato Regional Council said there was still contaminated sediment built up at the mine entrance and in the stream below, which flows directly into the Ohinemuri River.
This means if it rains again, more orange plumes can be expected in the Ohinemuri.
