The benefits of circular urban planning

A growing trend in urban planning is circular cities. Examples of this style of urban design are seen in cities such as Berlin, Germany and Malmö, Sweden. These cities are shining examples of the benefits circular urban planning can offer us in terms of sustainability and environmental protection.

This trend comes at an important time where currently more than half of the world’s population lives in cities, and this is only set to increase by two-thirds in 30 years. This increasing population is putting high demands upon our earth. Circular urban planning is achieved through understanding the ideas behind circular economy and “using nature as a template,” with the incorporation of ‘green infrastructure.’

Green infrastructure is a strategically planned out area, involving natural and part-natural resources in urban areas. It is put in place to help combat pressures on the environment caused by the large metropolitan areas and the large number of people they house.

Listed below are some of the key attributes involved in building a circular city as expressed by Daniel Johnson from Fast Company.

Reducing waste through green infrastructure

Waste is significantly reduced when creating a circular city. This is done through using green infrastructure in construction. Doing this mitigates waste in the building industry as the green exterior surfaces have greater longevity. For example, green roofs survive better against harsh weather systems, as well as intense heat from the sun. If the traditional flat roofs of buildings are covered with greenery, they are proven to hold strong and stable for twice as long as without the greening. Berlin has green roofs which are around 100 years old!

Alongside green roofs, green facades also have an important role to play in reducing waste. They provide a strong, protective layer against harmful weathering and hot temperatures from a fierce sun, reducing the amount of times a building must have maintenance checks.

These two simple measures incorporating nature into the way we build our cities, means we reduce the amount of waste used in the building industry and our buildings last much longer. This all results in the creation of a circular city.

Storm water as a resource

Green infrastructure also significantly helps in the management of stormwater in cities. What usually happens during the rain, is stormwater runs off concreted surfaces, into drains then into wastewater treatment plants. During heavy rainfall, the capacity of these treatment plants can often be greatly exceeded, resulting in stormwater and sewer water combing and polluting our rivers and oceans. Further runoff from the streets can add more pollutants to our waterways, contaminating our water systems.

Green infrastructure acts as a sponge, reducing the amount of water runoff, mitigating flooding and increasing the water supply, plus it also works to minimise energy consumption at the wastewater treatment plants. It replicates the way nature copes with rainwater.

There are several cities which have already incorporated green infrastructure for these purposes. Brooklyn, New York has a ‘sponge park’ which is helping to clean up Gowanus Canal, a river running through the suburb which is greatly affected by pollution. Since 2009, Toronto in Canada, has made green roofs obligatory to try and manage stormwater.

Also, on the other side of the world, in China, they have started a ‘sponge city initiative,’ mitigating and reusing the rain runoff. Berlin has also incorporated circular urban planning into its city design in order to reduce the negative effects of stormwater. For example, Potsdamer Platz, with 30,000 square meters, has an entire area of connected green roofs, natural spaces and a treatment pond for dealing with stormwater. Because of this natural pond, less energy is needed to clean the water, which then goes on to be reused for flushing toilets, and irrigation needs.

Energy consumption

The reduction of energy consumption at treatment plants, as well as through the use of green roofs and facades, does a great job in reducing carbon emissions. The green infrastructure also provides an extra layer of insulation, as well as protection against hot temperatures, meaning indoor temperatures are kept cool in summer and then kept warm and cosy in winter. Through reducing the use of heating and air conditioning mechanisms, a building’s greenhouse gas emissions are also reduced, helping the whole city to mitigate the effects of climate change.

The natural wall and roof coverings, also help to absorb pollutants such as carbon dioxide, nitrous oxide and sulphur oxide, from the air.

What other benefits are offered?

Lastly, green infrastructure is aesthetically pleasing and brings colour and nature into often grey and dull cities. People enjoy getting out into nature, with numerous health and wellbeing benefits on offer. Increasing the green within our cities, through incorporating nature into our infrastructure is thus doing a whole lot of good. Urban planners should be investigating these beneficial effects of circular cities.

What are your favourite ways to bring nature into our cities?