19 Nov 2020

Councillors and locals sick of toxic sludge recurrence on Wellington beach

10:05 am on 19 November 2020

A toxic sludge has again poured onto a beach on Wellington's south coast and there are no plans to permanently stop it.

Water at Houghton Bay in Wellington which contains the toxic substances.

Water at Houghton Bay in Wellington which contains the toxic substances. Photo: Supplied

The runoff comes from an old tip under the suburb of Houghton Bay which closed decades ago.

Since then periodically after heavy rain, it overwhelms the wastewater system and spews out onto Houghton Bay beach - and residents and local councillors are sick of it.

Houghton Valley resident Anj Barton said the recurring smell in the valley from the old dump reminded her of the stench of roadworks - old rubber tyres, tar and diesel.

"A lot of people walk their dogs on the beach as well. So ... people are smelling and breathing these fumes in which is pretty awful to be honest."

The toxic substance causing the smell called "leachate" is runoff from the old dump, with crews out last night cleaning it up.

When the wastewater system is running smoothly leachate is diverted to a treatment plant, but a couple of times a year - at random - it overwhelms the system and discharges onto the beach.

It is not known what triggers the runoff overflow, given yesterday's rain was nothing on the heavy fall of last week.

Tests in 2013 showed the substance has low toxicity and its effect on the environment is minor - but it is not known what was thrown into the tip all those decades ago, so it is possible the toxicity could increase over time.

Crews cleaning up toxic sludge washed out from the old tip at Houghton Bay in Wellington.

Crews cleaning up toxic sludge washed out from the old tip at Houghton Bay in Wellington. Photo: Supplied / Wellington Water

Wellington councillor Fleur Fitzsimons, who holds the health portfolio, said locals were fed up and deserved better.

"Residents sick and tired of this happening, surfers are sick and tired of this happening, and this community really deserves transparent answers about why it's happening."

Fellow councillor and Houghton Valley representative Teri O'Neill is pointing the finger squarely at Wellington Water, saying once again the organisation's mitigation strategy to stop the contamination had failed.

"When we have high water pressure that's supposed to trigger an alert to Wellington Water.

"This is exactly what we pay them to do and obviously something's not worked here today and that's what we're pretty disappointed about."

She said currently there were no large scale remediation plans to stop it the problem for good.

"If we were to say that no runoff could ever come from the landfill that would probably [require] ripping up an entire community given how much of Wellington homes and infrastructure are already built on the top of landfills."

Wellington Water stormwater adviser Ben Fountain said it was an issue that had been brewing for a generation and would required everyone working together for a permanent solution.

"This is certainly one that we need to be thinking about a longer term solution but it's going to take some time to develop and we'll have to involve a number of parties including Wellington City Council and ... the local community as well."

In the meantime, officials say people should avoid the beach for a couple of days.