Green infrastructure in water-sensitive urban design fundamental

Christchurch roadside raingarden and densely planted trees provide beauty, shade, and WSUD. Photo: Robyn Simcock, Landcare Research.

Urban areas typically alter landscapes from vegetated ground, which is able to absorb water, to a series of interconnected hard surfaces that result in large quantities of storm-water runoff scouring our waterways. In addition, this run-off can be polluted with contaminants such as metals, motor oil, garden pesticides, litter, and sediment.

This run-off requires management, but the Building Better Homes, Towns and Cities Water Sensitive Urban Design (WSUD) team says this isn’t just a matter of guttering in the right place and piping the excess straight to waterways, but also aesthetically pleasing urban lay-outs that promote water re-use and enhance urban liveability and human wellbeing.

Team leader Robyn Simcock, from Manaaki Whenua – Landcare Research, says they’ve found that Green Infrastructure (GI), the use of a network of natural systems involving soil and vegetation, used in WSUD is fundamental to achieving wellbeing – rather than just being ‘nice to have’.

“Without it, the benefits of money spent on buildings can be negated, as outdoor landscapes can optimise liveability and expression of kaitiakitanga. International studies show benefits of GI are greatest where social deprivation is high – it’s a way to improve social equity and health.”

Robyn says New Zealand may the best place in the world to implement WSUD, “Many areas have a temperate climate with frequent rain and year-round plant growth, and passing storm water through plants and soil instead of piping it straight to streams aligns with kaitiaki values. WSUD has been used in New Zealand for more than 10 years, but barriers remain to its widespread adoption, and in many places its full benefits haven’t been realised – especially its community liveability benefits.”

The wellbeing benefits of Water Sensitive Urban Design and GI are summarised in a report, Assessing the Full Benefits of WSUD, the team has also developed the ‘More than Water’ Tool to help communities, designers, and funders compare the nature and extent of benefits of projects with and without Water Sensitive Urban Design.

The benefits report, led by NIWA’s Jonathan Moores, says that the assessments of the benefits of WSUD that focus solely on these water-related outcomes are incomplete in their scope. “WSUD has the potential to deliver a wide range of other environmental and social co-benefits, for instance: the preservation of natural soils; microclimate moderation; terrestrial habitat provision for native biodiversity; the provision of supplementary water supplies; better public safety; and improved health and wellbeing deriving from the use of green infrastructure.”

Researchers Troy Brockbank and Emily Afoa, who have been investigating the overlap of te ao Māori and WSUD, say the principles of WSUD and intended outcomes are interwoven with the fabric of te ao Māori. “Rather than trying to integrate te ao Māori into WSUD, we should consider the different perspectives in parallel avoiding compartmentalising cultural values. Design through the lens of te ao Māori, applied as a mainstream principle through the WSUD framework, will empower the desired social and environmental connections to create resilient and healthy communities.”

The BBHTC Water Sensitive Urban Design team is a collaboration between Robyn Simcock, Manaaki Whenua – Landcare Research (plants and soils, WSUD maintenance); Jonathan Moores, NIWA (assessing environmental effects of WSUD); Sue Ira, Koru Environmental Consultants, (implementation and costing WSUD); and Chris Batstone, Batstone Associates, (indirect benefits of WSUD).

Publications available from the BBHTC Water Sensitive Urban Design team

2019

2018

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