Criticism at lack of action over rising contamination in Wellington's Owhiro Stream
A Wellington stream was so choked with pollution the landfill company investigated for adding a toxic cocktail has been put on a kind of water quarantine.
Greater Wellington Regional Council ordered T&T Landfills to divert water around its site and create a filtering wetland as part of a fix-it job on Owhiro Stream.
Council environmental group general manager Nigel Corry said water had run through the landfill down a gully and had "effectively become a tributary", with raised ammonia and iron levels, to the stream.
Now the landfill would have to divert the water above the site through a drain so it would enter the stream "clean".
Any remaining water and contaminants that leached out of the landfill would be treated by the wetland.
Corry said he did now know the exact deadline for the work but the water diversion had already been a condition of the landfill's resource consent.
A Greater Wellington investigation showed a slump in water quality and "significant adverse effects" on invertebrates.
The investigation came after it was discovered last year that a harmful discharge was flowing from the landfill, leaving the stream foamy and discoloured.
Greater Wellington found increasing levels of ammonia, iron and manganese, and T&T Landfills was told to remedy the problem and could face punishment for breaching its resource consent.
Paul Blaschke, an ecologist and lecturer in environmental studies and public health at Victoria University and Otago University of Wellington, said people in the Owhiro community had suspected for a long time there was a problem with the landfill.
He said diverting water away from the landfill was a good move, but he questioned whether it would fix the problem completely.
Mike Joy, a senior lecturer in environmental science and ecology at Massey University, said the ammonia that was wiping out invertebrates was guaranteed to be killing fish as well.
"Ammonia is lethal. And it will continue to be lethal until it gets diverted downstream."
T&T Landfills manager Sophie Gray did not want to comment on whether it would comply with the council's orders, other than to say "we're doing what we can".
Kevin Hackwell, the campaigns and advocacy manager at Forest and Bird, said the GWRC report showed the problem had been worsening over years. He questioned whether the council had been too slow in its reaction.
"The disappointing thing is that the sampling [of invertebrates] has shown a steady decrease over time. The number of species at the stream [at the bottom of the landfill] was just eight, compared with 23 at other stream sites.
Hackwell said the proposed solutions were the correct way to go. "Cleaning water is very hard and phenomenally expensive. The best thing is to stop pollution in the first place, so diverting water does make sense.
"But local councils need to be absolutely improving their monitoring, and insisting on best practice consents being met."
In December, the council launched an investigation into T&T Landfills' practices and issued it with an abatement notice under the Resource Management Act, meaning it had to comply with consent conditions or face a fine of up to $200,000, or two years' imprisonment.
The company had begun construction on both wetland and stormwater construction.
The consent breach was still being investigated and a decision on any punishment will be made by late May.