Beachside residents frustrated by swarms of midges disrupting daily life have received an update from Coastal Councillor Celeste Donovan, who has been working to address the issue.

Donovan said the swarms, which have forced locals to keep their windows and doors shut and made it difficult to hang out washing, have left many feeling as though they’re living through an “apocalypse.”

In response to the situation, Donovan organised an onsite visit to the Christchurch Wastewater Treatment Plant’s oxidation ponds to assess the issue alongside council staff. She said the visit provided an opportunity to discuss the causes of the

 

infestation, current management efforts, and potential solutions for the short and long term.

“The midges are not only a nuisance, but they’re having a significant impact on the community,” Donovan said. “We’re working on ways to provide more timely information and address the problem as effectively as possible.”

What are midges?

Midges are small flies, similar to mosquitoes, that live for about 36 hours and often form large swarms in warm weather. They are attracted to light and tend to settle on light-coloured surfaces. The midges breed in still, fresh waters such as those near the Avon-Heathcote Estuary, Lake Ellesmere, and Horseshoe Lake.

The Christchurch Wastewater Treatment Plant’s oxidation ponds provide an ideal breeding ground for midges due to the treatment process, which creates conditions favourable for algae growth – a key food source for the insects. Despite being a nuisance, midges are an important food source for many wetland birds.

What’s causing the issue?

Recent wet weather has boosted algae growth in the oxidation ponds, creating ideal breeding conditions for midges. While the rain has improved the biological health of the ponds, it has also led to an increase in the midge population.

Previous management efforts

In the past, the council has used various methods to manage midge numbers, including dredging the pond base to disrupt their lifecycle, altering water flow to make conditions less favourable for larvae, and planting native vegetation to create a natural barrier. Increased birdlife in the area has also helped to control their numbers.

However, Donovan said this year’s conditions have made management efforts more challenging. Dredging, for example, risks disturbing the fragile ecosystem of the ponds and could result in odour issues lasting up to a month.

Next steps

Council staff are closely monitoring the situation, and a shift in wind direction expected in the coming days may provide some relief.

Donovan is also encouraging residents to share their observations to help the council track and manage the problem effectively.

Residents are asked to report:

•Where they are seeing midges

•When the midges first appeared

•How long the swarms have been present

Feedback can be submitted via the Christchurch City Council website, the Snap Send Solve app, or by phone.

“I know how frustrating this is, and I want to thank everyone for their patience as we work through this,” Donovan said. “I’ll continue to provide updates as new developments arise.”

For more information on the council’s efforts to manage midges, visit the council’s website.