Rooftop garden will purify university's water

Passers-by will never see the secret the University of Otago's new psychology building is hiding.

High above the campus, the six-level building on Leith Walk has a roof garden - not a space to be admired or sat in, but one contributing to the building's rainwater collection and recycling system.

Row upon row of native plants will purify rainwater before it is delivered to tanks in the basement and recycled, to flush toilets and irrigate other gardens.

A postgraduate student from the botany department was monitoring the plants to ensure they were the best varieties for Dunedin, university property services director Barry MacKay said yesterday.

"We are not aware of another Dunedin building which has incorporated a roof-top plant purification system [for water]. The aim is to establish what sort of plants grow best . . . in the aggressively salt-laden air we have in this part of the city."

The $25 million building is almost complete.

Administration staff began moving into levels one and two last week and research groups and students would move in progressively between now and June, Mr MacKay said.

It is one of the first New Zealand buildings built to national Green Star education category standards.

Mr MacKay said it "cost a bit more" to incorporate green features during construction.

"But generally, you have much lower operating expenses, so you recoup the cost quite quickly."

He said he was "very pleased" with the building.

"It has a nice feel, and it is well finished.

"It is a credit to the designer, the contractor and the staff from my department who managed the construction process."

allison.rudd@odt.co.nz

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Innovative green features
- Rainwater collection and recycling system.
- Double glazing.
- Extra insulation.
- Recyclable carpet tiles Wood-chip burner.
- Low-energy artificial lighting which automatically turns off in daylight or when people vacate rooms.
- Extensive natural light.
- Sunshades doubling as walkways for cleaning windows.
- Adjustable wooden louvres.
- Opening windows to lessen dependence on air-conditioning.
- Secure bicycle storage area in basement.
- Environmentally-friendly paint and finishes.

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