The city where new housing is in doubt due to old sewer pipes

Tuesday, 28 March 2023

Wastewater capacity is raising questions over the city’s ability to meet government demand for more infill housing.

New housing is likely on hold for a big chunk of Hamilton because old sewer pipes can’t meet demand.

More frequent sewage spills from under manhole covers and pump stations in the south-west is part of why the council is now taking a more restrictive approach to development in parts of the city.

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It raises questions over the city’s ability to meet government demand for more infill housing under the ‘three by three’ policy that allows three dwellings up to three storeys tall in the suburbs.

While the council insisted it was “very much open for business”, in a statement it admitted it “might not be able to immediately approve new resources consents and three waters connections in some areas where the increasing demand is impacting networks and our environment”.

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The under construction pump house at Peacocke will be the “heart” of the transfer station, with four pumps that can each move 330 litres a second of water, thereby being capable of emptying the equivalent of an Olympic swimming pool in 30 minutes.

Suburbs – including Bader, Deanwell, Fitzroy, Glenview and Melville – are defined as high-risk areas with “limited or no capacity” for development due to wastewater capacity constraints.

A high-risk definition was based on network performance during wet weather events, modelling and consenting activity.

Officials said areas the furthest from the Pukete Wastewater Treatment Plant could particularly be affected by spills because pipes there were smaller and more prone to reaching their handling capacity quicker.

Growth general manager Blair Bowcott said it was hard to quantify the impact of the new consenting regime.

Parts of Claudelands, Fairfield, Hamilton East, Hillcrest and near the university are also being looked at “closely”, as were “isolated pockets” including small areas of St Andrews, Rototuna and Nawton.

Under the new approach, where a resource consent has already been granted the council will continue to connect developments in high-risk areas. For projects with a consent application in progress the council will undertake an assessment “on a case-by-case basis”.

But new proposed developments in high-risk areas, for which no application has been made, will see the council consider infrastructure needs “and likely advise that service connections will not proceed until our investments can ease any capacity issues”.

“A resource or building consent application will be processed in the normal way but resource consent approval provides no guarantee that a service connection will be approved.”

Hamilton City Council development general manager Chris Allen says it’s important the wastewater system isn’t overloaded so that the environment is protected from spills to waterways (file photo).

The council was also reviewing its connections policy and “it is likely there will be a stricter criteria for new three waters connections in high-risk areas of the city until long-term infrastructure solutions are implemented”.

The council’s move comes as the city is under more pressure from central Government to intensify housing generally.

Hamilton city started sharing its wastewater-related concerns with developers more widely on Tuesday after having been in discussions with bigger operators about the situation for some time.

Development general manager Chris Allen said there were more frequent overflows of diluted sewage during big rain events from under manhole covers and elsewhere. This could get into waterways.

“I guess the environmental impact is overflows … it’s starting to happen in the western side.”

Bowcott said increased housing intensification over the past decade had placed a greater strain on the three waters system. More people were living on smaller sections and new rules meant infrastructure needed to perform to a higher standard.

He didn’t have a number for how many developments the more restrictive approach might affect. “It’s hard to put a number on that one.”

Allen said identifying the scale was “part of the reason for having the conversation” with developers.

Getting the “balance and pace” of development right to avoid problems was important, said Allen. There was always a standing need to match new infrastructure with growth. Getting the timing of investment exactly right was challenging.

On whether the new approach could affect availability and affordability of housing in the city, Bowcott said: “There will be some impact.” But this was hard to quantify.

Allen, however, noted there were plenty of areas where developers could still “go for it”, such as the Peacocke subdivision and the central city.

“We’re not stopping development. We’ve just got to align it with our infrastructure investment programme and protecting the environment.”

Bowcott said developers they’d spoken to already were keen to talk about individual matters as they arose. “They understand and appreciate the issues we’ve been talking about.”

On why more hadn’t been done already to sort out potential issues in high-risk areas, Allen said the Peacocke subdivision infrastructure would help manage sewage in the south-west better and a number of other infrastructure initiatives were in train to improve things as well.