As a civil engineer with over 16 years of...
It’s now accepted that green infrastructure – using soils, trees and other planting to manage water in urban environments – is one of the best ways to prevent flooding and improve neighbourhoods. In fact, after deciding to develop green infrastructure, not a single city has turned back to do things the way they used to.
But as was reinforced at the recent Future of Urban Water workshop in São Paulo, some cities still struggle to implement green infrastructure. Every city is unique, so the solution – and the process to get to that solution – is different for each one. Based on the recommendations set out in Arup’s Cities Alive research and my experience, there are six mechanisms for successfully implementing green infrastructure in cities.
1. Overarching vision
Projects should be part of a large-scale strategic vision for the city or neighbourhood. The vision should identify the assets, opportunities, risks and vulnerabilities for the city in question. The 2010 NYC Green Infrastructure Plan (which was part of PlaNYC, the sustainability vision for the city) is a great example.
Green infrastructure unites different disciplines and interests, and that facilitates collaborative working. Crucially, competing priorities can often complement each other – such as integrating green infrastructure with traffic calming measures. The city of Melbourne has worked collaboratively with surrounding councils, Melbourne Water, state government agencies and rate payers to develop its WaterMark and Urban Forest strategies.
You need evidence to ensure you choose the right interventions for your city. It’s particularly important to understand the value of a city’s natural resources so you can plan how to enhance them. For the Llanelli Rainscape Green Infrastructure programme in Wales, the selection of three priority pilot schemes (Queen Mary’s Walk, Stebonheath School and Glevering Street) was based on a multi-criteria analysis. This included the key indicators such as surface water reduction, resolution of flooding, whole-life costing, ease of construction and carbon footprint. Post-construction data collection was critical.
4. Tools and the design stage
Planning is vital. Designers should ensure that green infrastructure is integral to any development, and that it is linked to the vision and framework for the city. This can be accomplished by providing standards and guidelines for consistency across large-scale implementation.
Maintenance of green infrastructure should be factored in from the outset with partnerships established at inception (such as engaging with a parks or natural resources agency to support maintenance). This will ensure its longevity and make sure the interventions reach their full potential.
In most cases, local authorities have funded green infrastructure. But this type of funding is now harder to secure, leading to new and innovative ways to fund projects and use resources. These methods include leveraging current capital improvement projects in Melbourne, building a shared investment for both green and grey infrastructure as New York City has done or using a stormwater credit trading programme as in Washington D.C.
At the São Paulo workshop, it was clear that stakeholders understand the drivers of change and how green infrastructure can create a water-resilient city. We discussed these mechanisms for implementation, and identified the different barriers to each.
However, the overarching mechanism for implementation is community action. If one stakeholder can create the right vision, this can lead to evidence or demonstration projects, generating momentum and collaboration. Once you have collaboration, tools, funding and management follow.
As an example, the green infrastructure at Hunters Point South in New York City was designed at a time when there was no published green infrastructure plan for the city or even a designated department within the city to provide accepted design standards or facilitate review. Rather than letting go of a good idea, we figured it out with all the stakeholder agencies, resulting in demonstration pilot projects. To achieve this, we built collaboration across multiple agencies and provided the tools (standards) to facilitate discussions and review.
The green infrastructure in Hunters Point South represents an idea within a funded capital infrastructure project. Projects such as Plus Pool and Lowline grew from a good idea and citizen action. From my own experience at Arup, I’ve learnt that there is always a way to realise a good idea. A citizen with a good idea can be very powerful and small steps on the right path will soon build momentum.