Making New Zealand Green Again - A 'Living' Roof Story

Zoë Avery (The Urbanist + Waipapa Taumata Rau, University of  Auckland), Hillary Johnston (Tektus), Emily Afoa (Tektus), Rachel  Devine (Auckland Council, Healthy Waters)

Auckland Council has installed a living roof (green or vegetated roof) on the Auckland Central City Library in response to delivering climate change targets and raising awareness of the environmental, economic, social, and cultural benefits living infrastructure can provide.

Living roofs are becoming increasingly common in cities worldwide for their ability to improve climate change adaptation, energy conservation, food production, and the potential to develop more sustainable and environmentally friendly living environments. Rapid population growth, advanced stages of urbanisation and the alteration of the natural environment defined by increments of hard impervious surfaces, pollution and a lack of contact with nature underline the importance and relevance of green infrastructure solutions, such as living roofs. Despite this, in New Zealand, living roofs are rarely included in developments, and if they are, most are being designed in isolation.

This paper outlines the multiple stormwater management benefits of living roofs, including reducing runoff and improving runoff quality, ultimately reducing some of the pressures placed on the public stormwater network and the receiving environment. Additional recognised benefits that are important for climate change adaptation and sustainability within our cities will also be described, including enhanced biodiversity, energy savings, urban heat island mitigation, air quality improvement, noise reduction, biophilic amenity and resulting human productivity improvements, and increased real estate values.

Some of the actual benefits will be measured and quantified using the Auckland Central City Library Living Roof as a local test case. A comparison study is proposed utilising a replica of the installed living roof, the pre-living roof as control, alongside several other options. This paper will describe the monitoring methodology and programme that will take place over the next five years to help Tāmaki Makaurau understand the benefits from both a building owner and the broader environmental perspective.

The paper also describes how the living roof installation responds to Auckland Council’s desire to lead by example in meeting environmental objectives related to our changing climate. The paper will outline the current legislation and some of the overseas possibilities through policies or incentives that have been found to support better outcomes. The overall monitoring project aims to discuss the legislative differences that encourage the uptake of living roofs in cities and to educate and raise awareness of the benefits of living infrastructure.