Hundreds of tyres are contaminating Porirua Harbour with poverty, laziness and formerly unfenced tyre yards to blame.
Since October, volunteers have removed 200 tyres from the mouth of Porirua Stream and there are at least 200 more still in there, said Porirua Harbour Trust chairman Grant Baker.
That is on top of 500 tyres dug out of the harbour five years ago by Porirua City Council and there may be more yet to be discovered. Jet-skiers have told Mr Baker they often stand on tyres after falling into the water.
Heavy metals in submerged tyres leach into the sea floor, killing plants and animals, he said.
"They can end up basically robbing the sea floor of any goodness and then kill it."
The trust plans to plant the estuary with sea grass but needs to clear the rubbish or the plants will just die, he said. Sea grass helps restore nutrients to the sea floor, encouraging the return of aquatic life.
Porirua is one of the country's main breeding harbours for fishing species, which the tyres are putting at risk, Mr Baker said.
Some tyres were washed from unfenced Kenepuru tyre yards backing on to the stream during floods six years ago. Since then the yards have been fenced.
But many tyres have been dumped more recently, either from the motorway ramp at Parumoana St or further upstream, he said.
Porirua Stream starts at the top of the Ngauranga Gorge and passes through Johnsonville, Churton Park and Tawa.
Some people will be dumping the tyres out of laziness or ignorance and many will be trying to avoid the $4.50 it costs to dump a tyre at the landfill, he said.
Porirua City Council harbour strategy co-ordinator Keith Calder agreed. Most tyre companies charge a mandatory fee to dispose of tyres but some people change their tyres themselves and can't afford to dump them. Attitudes need to change, he said.
"It's reflecting how we feel about the harbour, because it doesn't look very nice."
The council and trust plan to work with groups and schools to spread the message about litter in the harbour, he said.
"The challenge is how do you get these key messages out and provide people with a real incentive, whether morally or ethically, to actually clean up their act? We need the community's help."
BE HARBOUR FRIENDLY
- Rubbish and tyres belong in the landfill
- Everything that flows into street drains ends up in the harbour
- Wash your car on the lawn, not concrete, so the dirty water is soaked into the grass
- Dig a hole in your garden to wash paintbrushes in
- Kapi-Mana News