“London will be a National Park City where more than half of its area is green […]”. This ambition comes from London’s Environment Strategy. In order to achieve it, London will need more green infrastructure, and planning and design of new developments should aim to incorporate green infrastructure and sustainable drainage as much as possible. In this blog post, we take a look at what green infrastructure is and what the benefits are.

What is green infrastructure?

‘Green infrastructure’, includes parks, playing fields, private gardens, allotments, green roofs and walls, and cemeteries. The term refers to ecological processes rather than colour, so includes sustainable urban drainage systems, wetlands, rivers and canals, which are also sometimes referred to as ‘blue’ infrastructure.

There are multiple benefits resulting from green infrastructure, including improved resilience to severe weather and climate change, better air and water quality, the encouragement of walking and cycling, and enhanced biodiversity. In this blog post we look at how the transport sector and wider planning community can support green infrastructure.

Natural England also has a green infrastructure typology:

• Parks and Gardens – urban parks, Country and Regional Parks, formal gardens
• Amenity Greenspace – informal recreation spaces, housing green spaces, domestic gardens, village greens, urban commons, other incidental space, green roofs
• Natural and semi-natural urban greenspaces - woodland and scrub, grassland (e.g. downland and meadow), heath or moor, wetlands, open and running water, wastelands and disturbed ground), bare rock habitats (e.g. cliffs and quarries)
• Green corridors – rivers and canals including their banks, road and rail corridors, cycling routes, pedestrian paths, and rights of way
• Other - allotments, community gardens, city farms, cemeteries and churchyards

Charter Square, Sheffield. Full access to case study of this project available to CIHT Members here.

Why is green infrastructure important?

Climate change is leading to more severe weather events such as heatwaves, droughts and heavy rainfall. The risk of flooding increases year on year, with more frequent and intense storms resulting in a build-up of significant quantities of surface water runoff, and existing networks of sewers can become overwhelmed: green infrastructure can help address these challenges. Green infrastructure and SuDS can be incorporated into multi-functional projects that both creates better places for people, enables movement and are better for the environment.

Green infrastructure also has a role to play in the creation of better places and according to the World Health Organization green urban spaces “support and facilitate health and well-being by enabling stress alleviation and relaxation, physical activity, improved social interaction and community cohesiveness. Health benefits include improved levels of mental health, physical fitness and cognitive and immune function, as well as lower mortality rates in general”.

Benefits of SuDS

SuDS deal with surface water to reduce the likelihood of flooding as water is held back at a source prior to discharging into the water system it is connecting into (a river water course or sewer or wider drainage network). Designers need to accommodate infrastructure systems to ensure they are future proofed when faced with heavier downpours. 

Another element is water quality, where SuDS can help remove the pollutants that are picked up on roads such as hydrocarbons and metals. Runoff from roads, for example, includes contaminants from tyre abrasion such as rubber and soot, nickel and chromium from brake pad linkings and oil, silt and iron oxide from general traffic use. SuDS and green infrastructure also support biodiversity, in relation to SuDS this could be ponds or swales that serve both a flood-risk mitigation measure but also support wildlife.

How can we as highways and transportation professionals incorporate more green infrastructure into our work? CIHT with a panel of experts will explore that question in a webinar on 17 March 12:45-14:00. You can book your place here.