22 January, 2020

Eco-drain spill pollutes Takapuna Beach

A pollution spill on Takapuna Beach was caused by council contractors cleaning out an environmentally friendly stormwater drain.

A resident alerted Devonport-Takapuna Local Board member George Wood, who traced the slurry on the beach back to council contractors washing out a nearby stormwater drain installed with a filter.

“It would seem that every time the operator flooded the catch-pit and stirred the sediment, the slurry water would discharge down the outlet pipe at the top of the catchpit,” Wood says.  

The water was being used to break up consolidated sediment at the bottom of the catch-pit, he says.

Wood believes the spill would not have happened if the stormwater catch-pits were cleaned out more frequently, ideally every four months.

He is critical of the state of streets since the super city was formed, saying the former North Shore City Council, of which he was once the mayor, was committed to sweeping streets and clearing out gutters and drains.

“If streets are not swept regularly and catch-pits also cleaned on a frequent basis, the efficiency of the pollution controls diminish,” Wood says. 

“This, I fear, is what is happening with the street-stormwater control system of the areas where stormwater discharges onto Takapuna and Milford beaches and also into Lake Pupuke.”

Wood has for several years been calling for the council’s healthy waters team to organise more frequent clearing of stormwater drains installed with pollutant filters.

They are currently cleared annually, but he says best practice is four-monthly.

Litter and contaminants from roads, such as tyre rubber, are significant sources of pollution for North Shore beaches, Wood says.

“We hear pollution is from infiltration of wastewater into stormwater, but it’s the rubbish on the roads, too.”

He is unhappy stormwater traps on arterial roads are cleared every six months, but in the Takapuna area, it’s only annually.

In a 20 December email, a member of the healthy waters team admits the traps are in need of maintenance and says the council is working with AT and a contractor to ensure they are maintained properly and on schedule.

This article originally appeared in the 24 January 2020 edition of the Rangitoto Observer.