15 September 2023
Jardins collectifs à Saint-Ouen entourés d'immeubles
A living laboratory for urban soil unsealing and renaturation is being designed by Cerema in Trappes (78). It is based on Nature-based Solutions (NBS), key elements to develop nature in the city.
The improvement of knowledge in this field in order to share it with as many people as possible, and the development of a network of stakeholder are two of the objectives targeted.

By bringing together on a single site operational works on a scale of 1, research and innovation projects, and educational facilities, this site will be a tool for raising awareness and training stakeholders (technical services, planners, elected officials, students, etc.). It will also allow the sharing of sustainable development methods.


Emerging issues

Vue d'un fossé aménagé avec de la végétation filtrante en ville

City planning must respond to numerous social and societal issues, related to climatic change. This implies sobriety, a fight against artificialisation through:

  1. the preservation of resources, paticularly the soil, a key element of the urban ecosystem,
  2. 2the deployment of nature-based solutions (NBS) (SFN) accompanying the unsealing and renaturation of soils.

Soil sealing is the ultimate stage of artificialisation, in which the ecological functions performed by the soil are greatly reduced or even completely lost: the soil is reduced to a simple support.

In order to take soil into account in city planning, we must consider its capacity to provide various services: source management of rainwater, (peri-)urban agriculture, biodiversity reservoir, improvement of the living environment, reduction of urban heat islands.

The deployment of nature-based solutions (NBS), building on the functioning of the ecosystem functioning, highlights the ecological functions of soils: rainwater infiltration and regulation of the water cycle, filtration of pollutants, source of biomass, carbon and biodiversity reservoir.


The project

In order to experiment and capitalise on knowledge of soil unsealing/renaturation techniques, Cerema is developing a project at its Trappes site (78) for a Living Laboratory for SFN in urban development. It is supported by the Ministry of Ecological Transition as part of the national action plan for the sustainable management of rainwater [2022-2024] and also by the by the Programme d'Investissement d'Avenir (PIA 4) CY Generations, supported by the University of Cergy-Pontoise.

Different techniques of soil reconstitution and construction will be implemented to illustrate the means of unsealing and renaturing the soils

In terms of stormwater management, 1:1 scale structures proposing alternative techniques to pipe network will be developed. The maximum disconnection of buildings and sealed surfaces will be targeted.

These different structures will be monitored over time, some of which will be structures will be monitored over time, some of them being instrumented, which will allow to evaluate their performance and the ecosystemic services provided.

The implementation process, knowledge gained and and results will then be shared with interested stakeholders. The project also aims to welcome innovation and research.


Studies and diagnoses are underway to define the characteristics and the hydrological functioning of the site (topography, hydrological diagnosis, fauna and flora, microbial biodiversity, etc.) and the buildings that could be used for roof greening


Developing a network of local stakeholders

The Living Lab project is carried out in a co-construction process with local and national stakeholders in water and soil management (City of Paris, SIAAP, Ademe, OFB, etc.), and research laboratories. Various working groups have been set up in order to specify and take into account the needs of future users.

The aim of the Living Lab is to create a local ecosystem of research and innovation, which will give an important place to citizens, users and planners of these of these Nature Based Solutions, to improve the understanding and their use and encourage their deployment.

Contact Cerema

Adress: Cerema - Île-de-France – 12 rue Teisserenc de Bort – 78190 Trappes 

In the folder : Nature en Ville : développer les solutions fondées sur la nature dans le milieu urbain

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