As we become ever more numerous on this blue planet, we are also building ever more. Unfortunately the artificialisation of soils, and their resulting impermeability, can have severe consequences for biodiversity, aquatic ecosystems and rainwater management, as well as for the health and quality of life, of urban residents.

Combating ground impermeability, through rendering it more permeable and renaturing, is therefore essential in strengthening the resilience of inhabitants facing climate change – such as drought and flood – and for preserving our flora and fauna.

As encouragement, in France a range of subsidies and grants are offered to regional public authorities, landowners and other economic players whose planning projects address the challenges of sustainable rainwater management.

Financing programmes to improve ground permeability

Various subsidies and grants are available for projects that incorporate actions for restoring the large water cycle and adapting to climate change (green roofs, permeable parking areas, cool islands, de-artificialisation and improving of permeability of soils, etc.). Calls for projects are also regularly announced.

These subsidies are mainly obtained from water agencies, regional authorities, regional Environmental, Planning or Housing offices (DREAL – directions régionales de l’Environnement, de l’Aménagement et du Logement), or the French Office for Biodiversity.

Note that the Aide-territoires [Regional Assistance] mechanism gives authorities an overview of all the financial assistance available to them, while the CEREMA, ADEME and ADOPTA websites also provide useful information.


Water agency subsidies

The “Water and Climate” programmes offered by the water agencies provide financial assistance in the form of grants to planning projects which address the issues involved in the sustainable management of rainwater. These programmes target schemes for permeability improvement, greening or the penetration of normal and heavy rain into open ground, for example. This assistance can cover up to 80% of the total cost of the works.

The water agencies also regularly launch calls for projects intended to promote such initiatives. For example:

  • Some authorities have benefited from grants to enable them to start ground permeability improvement projects to break the linkage between rainwater and hard drainage infrastructure.
  • Projects for managing rainwater at source which prioritise Nature-based Solutions have enabled a number of industries and companies to also benefit from water agency subsidies.


Regional authority subsidies

Regional authorities have specific subsidy funding for achieving the Sustainable Development Goals published in their plans. These include the European Regional Development Fund (ERDF), managed by the DREAL, and the Green Fund, managed by local authorities.

In this way, city and local authorities offer financing for numerous projects on specific themes, such as:

  • Primarily targeted at these authorities, the “100 cool islands” call for projects launched by the Paris Region offers grants of up to 60% of costs (design and planning work) for projects in urban heat island areas. These subsidies apply to projects for the creation of cool islands in urban public spaces, educational establishment open areas, and establishments open to the public, that are able to implement initiatives such as ground permeability improvement, greening, and alternative rainwater management.
  • The local authorities in the Loire-Atlantique department are financing up to 70% of the costs for deartificialising and renaturing impermeable ground (greening parking areas, green cycle routes, turfing of urban environments etc.) with a ceiling of €200,000 per recipient per year.

Worth knowing

As part of the “France Nation Verte” (France, Green Nation) ecological planning, the Green fund allows authorities and their public and private partners to finance projects particularly related to the renaturating of cities (greening, water management, park and garden development, etc.). The grants afforded are intended to finance the “regional diagnostic”, “study” and “investment” parts of the projects. In 2023, the Green fund supported over 200 hectares of renaturing projects affecting 1.95 million inhabitants.

Subsidies from the French Office for Biodiversity (OFB)

Each year, the OFB launches calls for projects related to biodiversity conservation. Renaturing and permeability restoration projects led by authorities or public establishments are welcomed.


How to benefit from these subsidies?

In order to benefit from these grants, the project initiators must put forward actions related to the subject matter of the particular subsidy (renaturing of soils and urban spaces, greening of buildings and amenities, flood defences, etc.) The scale and environmental impact of the project, or its local nature, are also eligibility criteria. It is therefore advisable to liaise with the appropriate authority.

In general, applications should include an overall description of the project (aims, location, plans etc.), details of the activities and timescale for each stage of implementation, monitoring and evaluation methods, provisional costs, financing plan, the consultation or decision of the project owner requesting the grant, and if necessary, the agreement of the particular authority responsible for urban matters (in the case of private projects) plus a table of grants and subsidies already awarded.

Depending on the type of subsidy requested, the project owner will send the grant request by mail to the applicable regional delegation or will upload it via the special Démarches simplifiées [Simplified processes] platform.


Why improving urban soil permeability matters?

Remember that the soil plays an essential role in water management, carbon storage and housing biodiversity (flora and fauna). However, every year almost 24,000 hectares of natural, agricultural and forest area are lost beneath impermeable ground.

Human activity undoubtedly demands extensive built infrastructure (roads, parking, buildings etc.) but the materials used (concrete, asphalt etc.) do not allow rainwater to penetrate the ground,

preventing the soil from performing its role in filtering or managing rainwater. The consequences may be disastrous for the environment, the health and safety of inhabitants, or even for a region’s economy. Risks include:

  • The pollution of aquatic environments, and eutrophication: before merging back with the aquatic environment, rainwater flows over the impermeable surfaces, taking with it a number of pollutants which find their way into water courses, lakes and oceans. This is compounded by discharge from sewage works and runoff from polluted waters.

Ultimately, pollution accumulated in the aquatic environments may result in eutrophication (imbalance within the ecosystem, or even “asphyxiation”) and the loss of various plant and animal species, or it may make the water undrinkable.

  • Flood risks: rather than allowing rainwater to penetrate the ground, from where it feeds into water tables and the surrounding greenery, artificialisation increases their flow rate and can induce significant flooding.
  • Creation of urban heat islands: the heat island phenomenon is partially explained by the excessive presence of materials such as concrete and asphalt, which store heat then release it back into the air. However, it results primarily from a lack of shade-giving greenery and the existence of impermeable ground, which combine to limit evapotranspiration and prevent cooling of the surrounding air.

Improving the permeability of urban surfaces allows the ground (in open areas) to resume their role in water management and so avoid the risk of floods and drought. It is also a means of combating the heat island effect, so prevalent in cities and improving the quality of life of city-dwellers. And of course, this is a way to reinstate nature and preserve our crucial biodiversity.

This short video, produced by Sauvons l’eau, a site dedicated to water and stakeholders within the water industry in France and internationally, explains the need to improve ground permeability for us all.

Subsidies and grants for sponge cities

Sponge cities are the remedy, or one of the remedies, to the ailments of city-dwellers and their natural environment. By allowing the ground to filter rainwater, the virtuous permeability improvement of urban surfaces in effect combats heat islands, the risk of drought or flood, or the contamination of drinking water and loss of biodiversity.

Initiators of sustainable projects related to permeability improvement and the renaturing of cities can access significant grants and subsidies awarded by the water agencies, regional authorities or the French Office for Biodiversity. This is the opportunity for authorities, companies and other economic actors to participate fully in the ecological transition.


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