Endeavours to help improve water quality in the Tokomairiro River catchment have failed, with a new study suggesting it has deteriorated to the point of being one of Otago's most polluted waterways.
"It's got worse, considerably worse - it's the whole catchment, not just a pocket," Otago Regional Council chairman Stephen Woodhead, a South Otago farmer, told a committee meeting this week.
Results from a recent council seven-month study of the river's water quality found the entire catchment exceeded accepted levels for bacteria, sediment and nutrients - findings that made it the most polluted of the rivers on which the council had so far done intensive water quality studies.
It was considered a high-risk catchment because of its high rainfall, dominance of open and tile drains and the expansion of intensive farming, including 19 dairy farms.
Some of the most polluted sites in the study were drains in the Moneymore area, near Milton, which contributed to the west branch of the Tokomairiro River.
"That to me shows direct animal effluent going straight into the waterway, or there's something dead in there," Mr Woodhead said.
"There are some real challenges here. It does concern me."
Chief executive Graeme Martin said the council had put in much effort, over many years, educating farmers about water quality and best practice.
"It's fair to say this outcome is a major disappointment."
Given the contamination levels in the catchment it was going to be difficult to improve water quality and it would require the council to find "innovative new ways" to persuade landowners to do so, he said.
With changes coming to water quality regulations, through water plan 6A, the catchment might need more time to comply.
"It's the most difficult spot we've got."
Cr Duncan Butcher said the results were no surprise, but the hard thing would be how to fix it.
"It's going to take a long time to bring this catchment right. In reality, this can't go on."
Cr Gretchen Robertson said the community needed to be aware how serious the situation was and the long-term repercussions.
The report needed to be presented to the community and other affected groups such as Federated Farmers, she said.
Mr Martin said the council should call a meeting to present the information, including independent farming advice, and look at what action could be taken.
The committee agreed to Mr Martin's proposal.
Federated Farmers' Otago president Stephen Korteweg, who farms at Kaitangata, said he had not read the report, but such results needed to be taken seriously by the community and farmers.
"I suspect there will be a number of farmers who are shocked by this."
The pollution "hot spots" needed to be traced back to the source so work could be done to rectify the problem, but people needed to be aware it was not something that could be fixed in "five minutes".
"We need to find a sensible workable outcome. Urban or rural, we all realise we have to lift our game."
Fish and Game Otago environmental officer Peter Wilson said the organisation was very concerned about the report, which again highlighted the impact intensive land use was having on the region's waterways.
"It further reinforces the need for all of the community to back plan change 6A - if those standards are applied it will clear up the waterway."
Mike Barra, of Milton, who for many years worked alongside the Tokomairiro River, at what is now Bruce Woollen Mill, said most people blamed the pollution problems in the river on Milton wastewater treatment plant discharges over many years.
The town's fishermen might fish the lower and upper reaches of the river but none would fish its mid-reaches, he said.
The council report said while the plant had been upgraded, an audit this year by the regional council showed E.coli concentrations had exceeding the guidelines on two occasions.
