PROJECT STORY
The challenge
To preserve the quality of life in cities, heat must be limited. The Paris city council was forced to acknowledge this fact after successive summer heat waves, and decided to create five urban forests in the city.
Decarbonizing Paris and creating new green spaces
Creating urban forests in Paris for a cooler feel and cleaner air
The solution
Planting large trees in spaces made up entirely of concrete and steel is a challenge. Paris city council entrusted Arcadis with the project's feasibility study for three of the five sites selected.
The impact
Once the urban forests are created, Paris residents and visitors will be able to breathe cleaner air and have new green spaces in which to relax and cool off.
170,000
trees planted
100
hectares of asphalt to be transformed into a forest by 2026
5
new urban forests in Paris
The challenge
While the French capital is world-renowned for its rich architecture, it is often criticized for not providing enough green space for its inhabitants. Below the majestic Haussmann buildings, it is concrete that dominates and this predominance increases the temperature in the summer. Heat, absorbed during the day, is given off by sidewalks and roads at night.
In response to this and to cool the city down, Paris city council decided to create five urban forests in iconic locations in the French capital.
The solution
To turn Paris city council’s wish into a reality, Arcadis is carrying out studies and exploring all possible scenarios for the three of the five sites entrusted to it: the paved square of the Hôtel de Ville, the paved square of Euronext Paris, and Place Saint-Gervais located behind Hôtel de Ville, which will be the site of the future memorial of the Paris attacks.
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Adapting the ground, reinforcing its structure and ensuring it is watertight so that it can accommodate large trees is a real technical challenge. A great depth is required to create the large volumes that will house the soil needed to plant the trees. To do this, a very large portion of the first level of underground parking garages will be used to create the shell intended to hold the soil. The concrete slab will thus be lowered from one and a half meters to two and a half meters. This technical feat will allow trees to be planted across an area of 1,500 m² at the Hôtel de Ville, the equivalent of more than two basketball courts. Depending on the scenarios, Euronext Paris may be able to accommodate an area of 1,000 to 1,800 m². The remaining space, in level -1 of the parking garages, will be used for parking bicycles and motorcycles. Arcadis plans to reuse some of the materials from the demolition of the slab. Moreover, these transformations require a complete redesign of parking garage accesses and traffic flows, in order to leave as much space as possible for surface landscaping projects.
All the scenarios were modeled by Arcadis' teams in record time. The digital mock-ups allow the different scenarios to be visualized and assist with choosing between the various solutions imagined.
Arcadis has also conducted an environmental analysis demonstrating the advantages and disadvantages of each solution in terms of its carbon footprint. In particular, this study demonstrates how much urban forests contribute to creating cool relief and how important choosing the right materials is for limiting heat.
The impact
The planting of urban forests in Paris will transform the city's appearance and allow its residents and visitors to take advantage of new green spaces in which to relax, have fun and cool off. In addition to being good for mental health and well-being, trees help reduce air pollution, so Parisians can breathe better-quality air.
Beyond mitigating the effects of global warming and boosting land biodiversity, this project for the creation of green spaces and decarbonization asserts a new urban paradigm, in favor of the quality of life of residents.
