These free-standing living walls help reduce air pollution at the gateway to Southampton
Area: 260m2
Location: Southampton
System: BioPanel
Install Year: 2019
Client: Balfour Beatty / Southampton City Council
Number of plants: 11,000
As part of a major reconstruction project at Millbrook Roundabout, Southampton City Council wanted to create a visual landmark that would also contribute to improved air quality.
The roundabout sits beneath the Millbrook Flyover, one of the busiest road areas in the city, carrying around 36,000 vehicles each day. The area suffers from high levels of pollution, and in response to a 2015 air quality study, the council developed a city-wide strategy to tackle the issue.
They sought a solution that would help mitigate pollution, soften the visual impact of the concrete flyover, and provide a more welcoming gateway to the city, all while ensuring critical infrastructure remained accessible for inspection and maintenance.
Our approach
A key challenge was to conceal the concrete support columns of the flyover without attaching anything directly to them, as future structural inspections needed to remain possible.
To meet this requirement, we worked with structural engineering consultants to design a bespoke, freestanding steel frame with an arrowhead profile. This frame allowed our BioPanels to be installed in front of the columns, creating the visual effect of the bridge being supported by living wall structures, while maintaining access behind.
The planting design was inspired by the River Itchen, a local waterway of ecological significance that flows through the city. We selected 17 plant species, including Euonymus, Convolvulus cneorum, and Acorus gramineus, for their aesthetic appeal and their proven ability to capture particulate matter, aligning with the council’s air quality goals.
Design
Including panel layout, plant design and irrigation design
Horticulture
living walls grown in the nursery for 8-12 plants until fully mature
Installation
Installation of backing board, geotextile drainage layer, irrigation pipework and planted panels
Maintenance
Remote monitoring of the irrigation system, regular visual inspections and horticultural maintenance visits
The results
These living wall installations successfully transform a heavily urbanised and polluted gateway into a striking and environmentally beneficial landmark.
In recognition of its environmental impact and innovative design, the project was awarded a prestigious Gold Green Apple Award by The Green Organisation.
The BioPanel system is designed to last for years to come and is being looked after by Biotecture’s maintenance team.
The living wall project at Millbrook Roundabout is the first of its kind in the UK. It’s an exciting way to make our public spaces more attractive whilst at the same time having a beneficial effect on the environment. Investing in greening projects like this will play an important part in safeguarding our local environment for future generations.
