Search for pollutants looks into city drains

Urban stormwater is likely to be the next target in efforts to clean up New Zealand’s waterways.

Horizons Regional Council has started researching the type and quantity of stormwater discharges being made to the region’s streams and rivers, with a view to reducing contamination.

Group manager for natural resources and partnerships Jon Roygard told Horizons’ environment committee on Tuesday staff and consultants were working with council chief executives around the region on a stocktake.

‘‘We need to understand what discharges there are, and whether they are meeting requirements, and whether further consenting is required.’’

Horizons chairman Bruce Gordon questioned whether it was realistic to expect local councils to invest more in stormwater management when their budgets were already stretched to improve wastewater treatment.

Whanganui had spent $21 million on its wastewater, and Palmerston North would face even higher costs over the next decade for its upgrade.

‘‘If we spend a whole lot of time on urban stormwater, we are going to identify huge problems – we know that – but is it realistic?

‘‘We could identify something potentially quite serious, then not have the answer, because we can’t afford it.’’

Roygard said nobody had jumped to any conclusions about what would need to be done yet.

‘‘We need to understand the size of the issue, and where we need to focus our attention.’’

Roygard said reducing stormwater could have additional benefits in limiting the amount of infiltration into wastewater pipes that was putting extra load on treatment plants.

Cr Wiremu Te Awe Awe said urban stormwater runoff was the elephant in the room, which would have to be addressed.

But he said there were simple, small steps, like every home having a tank to catch rainwater off the roof, that could add up to make a huge difference.

Chief executive Michael Mccartney said there was no doubt the significance of stormwater management in achieving the goal of swimmable rivers needed to be better understood.

The National Policy for Freshwater Management required more work to be done in controlling urban stormwater, and it was likely to be part of the changes needed to achieve the goal of 90 per cent of rivers being fit for swimming by 2040.

Mccartney said councils needed to figure out what it was going to take to achieve that goal, and be up-front in estimates of what it might cost.

Tararua councillor John Barrow said the farming industry had had to make changes to manage its impact on waterways.

Now the focus was shifting to find out what changes needed to be made in managing urban runoff.

‘‘This is not about picking on one sector of society. It’s about keeping it real, and setting priorities.’’