The Otago Regional Council (ORC) has received more than 30 complaints of stormwater pollution and sediment discharge into water in the last two weeks, most of them in Wānaka or Dunedin. 

ORC manager compliance Tami Sargeant thanked the individuals who rang the council to advise them of cases where the sediment and stormwater controls had failed during the recent rain.

“The priority here is for people and businesses to check that sediment controls are in place and stormwater drains do not have contaminants going into them,” Tami said.

Some of the recently reported discharges came from consented development sites, small residential worksites which are unconsented, roadworks maintenance, oil changes on roads and from the washing down of concrete pads, Tami said.

There are a number of steps residents and businesses can take to reduce the risk of stormwater pollution and sediment discharge.

“We’re encouraging people to install sediment controls and to check that they’re actually in working order. They should also be aware of the stormwater rules,” Tami said.

“If the right controls aren’t in place, heavy rain can carry sediment from earthworks into our waterways.”

If people are unsure about the rules around earthworks, they should contact ORC’s consents team by emailing [email protected], or calling 0800 474 082.

During high-flow events some sedimentation occurs naturally, but sediments flowing into streams, lakes, and the coastal environment can be harmful for freshwater and marine ecology.

Using lawns, gardens and gravel areas are good ways to soak up and filter runoff from household activities, Tami said.

If liquid paint or plaster, cleanup washwater or solvent wastes make their way into the stormwater drain, the chemicals they contain can kill aquatic life, Tami said.

Tami said some of the highest risk areas are around residential developments, and developers must adhere to their consent conditions.

“There must be suitable erosion and sediment controls in place before earthworks begin, so as to minimise the risks of pollution,” she said.

Anyone seeing pollution around Otago should contact the 24/7 ORC pollution hotline on 0800 800 033, or email [email protected].

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PHOTO: ORC