Smelly Invercargill water costly for ratepayers

Hundreds of thousands of dollars have been spent keeping Invercargill water from smelling and tasting putrid during the past two decades, but the problem appears to be getting worse, according to the city water services manager.

Invercargill City Council water services manager Alister Murray said the city had regular problems with a bad smell and taste in its drinking water during summer months since 1995. Between $15,000 and $25,000 was spent each year addressing those problems but it appeared to be getting worse, he said.

Southland water issues were highlighted this week in a report from Auditor-General Lyn Provost, which criticised Environment Southland for its management of water quality risks.

Bad odour and taste in Invercargill drinking water first became an issue in 1976 and was sporadic until the early 90s, but since 1995 the problem had occurred every year except one, Mr Murray said.

Increases in nitrate levels in Southland rivers was believed to be one of the causes, he said.

The problem occurred for about one month each year, but could go on for up to three months and to prevent it the water was doused with activated carbon, Mr Murray said.

The city's water was taken from Oreti River at Branxholme, but when the river was running low it warmed up and caused the algal and soil bacteria to give off the compounds that caused the smell and odour, he said.

However, since nitrates flowing down the river were increasing from intensified farm run-off it may have prompted the algae to grow and cause the increased problem, he said. "Anecdotally, I think we can probably say the surface water run-off from farmland will promote algal producing compounds in the waterways and that is associated with the taste and odour.

"Whether we can attribute that to changing farm practices, there is anecdotal evidence but we don't have hard evidence – we would rather not have the problem, but we don't have control over our waterways," he said.

Environment Southland chief executive Ciaran Keogh said most farmers abided by the rules for protecting freshwater from land intensification run-off and while the nitrates could be contributing to the increase in the smell and taste problem, the waterways were in a dry phase, which often lasted more than a decade and meant the rivers ran low and the algae was not flushed regularly by flooding.

Mr Murray said the algal compounds in the drinking water did not pose a risk to health, but was unpleasant and people did not like to put up with it. People's tolerance to the problem had diminished in latter years compared with three decades ago and that was a major reason for the cost, he said. Gore District Council utilities manager Ross Haslemore said Gore residents did not have the same problem because their water was taken from a bore, but the council was looking for a new water source because of increases in nitrates in the water and an expected increase in demand.

However, the problem did occur in Mataura when the river ran particularly low, he said.

Southland District Council water and waste asset manager Ian Evans said the wider Southland district also took most of its water from bores so did not have the same problems.

- © Fairfax NZ News

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bruce   #3   10:00 am Sep 29 2011

I think this dairy thing has got way out of control and these farmers need to install more at thier end to prevent this happening as bad as it has.It's funny how we jeoprodise our biggest commodiety for a few dollars profit for a mesly few who benefit the rewards.

Guess Who...   #2   via mobile 09:17 am Sep 29 2011

*Clearly* the work of dole bludgers, out there dumping cow shi... sorry, "nutrients" and fert in our waterways, they must steal cars and drive about the countryside, on their rambunctious jaunts of drunken destruction!

Kevin M   #1   08:27 am Sep 29 2011

So "who" cleans the drains......."yuk"

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