Désimperméabilisons les sols urbains!

Occitanie faces water stress, and the conversion of permeable surfaces into impermeable surfaces through development exacerbates water stress and the natural water cycle. This is referred to as ‘soil sealing’ the process of covering soil with materials such as concrete and asphalt. Occitanie is one of the regions of mainland France (France métropolitaine) that converts the most natural, agricultural and forest land, at an average of 33 million m² per year. The share of impervious land- or artificial surfaces- in the region grew by 14.5% between 2005 and 2015.

The region has close to 5.9 million inhabitants. Between 2013 and 2018 it gained an average of 40,300 residents per year, a growth rate of 0.7% against 0.4% across mainland France. Each new resident accounts for an average of 730 m² of land used for housing, facilities and infrastructure.

Sealed surfaces disrupt the water cycle. They reduce groundwater recharge, increase runoff and flood risk, and carry pollutants into rivers and wetlands. They also cause combined sewer networks to overflow in wet weather. Sealed surfaces add to urban heat islands and remove space for biodiversity.

Occitanie is exposed to both drought and flooding and recent years have brought a succession of droughts and floods across the region. These extremes are expected to increase. They threaten water supply for all uses, infrastructure, and the natural environments and services they provide. Water management must adapt to these consequences at local level.

Reducing the amount of impervious surfaces manages water as a valuable resource, can protect water quality and ecosystems and manage urban flood risk and dangerous heat. Removing sealed surfaces restores part of the lost soil functions. The Région has made de-sealing urban soils a regional water priority.

This action takes an all-region approach to reducing impervious surfaces and encouraged co-delivery and ambitious approaches. The Regional Government of Occitanie (Région Occitanie / Pyrénées-Méditerranée) ran a call for projects that funded ambitious initiatives to remove sealed surfaces and manage stormwater through planted, permeable spaces. The Région delivered the call with the two water agencies active in Occitanie: the Adour-Garonne Water Agency (Agence de l’eau Adour-Garonne) and the Rhône Méditerranée Corse Water Agency (Agence de l’eau Rhône Méditerranée Corse). The water agencies are national public bodies under the Ministry of the Environment. Each sets water levies and a six-year programme of financial aid. Source 1 ↗ Source 2 ↗ Source 3 ↗

The call covered every sealed soil in Occitanie, from large urban areas to small town centres, in urban and rural settings. It sought projects that would:

• control the quantity and quality of water reaching rivers, wetlands and groundwater
• disconnect stormwater from sewer networks so that it infiltrates the ground
• bring nature into towns to restore environmental quality and biodiversity as the climate changes
• reduce the impact of urban runoff

Projects had to demonstrate several of these benefits together. The overall aim was a landscape-based approach to stormwater management in place of piped drainage alone.

The call was open beyond public bodies, which extended its reach to land the public sector does not own or manage. Four groups could apply:

• local and regional authorities and their groupings,
• public project owners such as public bodies, health establishments and universities
• landowners, including co-ownerships but excluding private individuals
• Private entities, companies and developers that own and manage land in the Region.

The call funded three categories of action:

• Building the Knowledge Base: including technical and economic feasibility studies, hydraulic and geotechnical studies, clarification of regulatory constraints, analysis of how permeable sites will function, land opportunities and comparative cost-benefit analyses.
• Delivery Actions: projects that worked to decrease impervious surfaces, and restore natural functions- works such as swales and rain gardens, disconnection of combined and stormwater sewer networks, planted green spaces using local species, and landscaped car parks with permeable surfaces.
• Awareness and engagement activities: activities aimed at site managers and the public that promote de-sealing and changes in planning practice. Every application that included works had to include this component.

Within works, only spending that achieves de-sealing objectives was eligible. Furniture installed on a green space, for example, was excluded. Local coordination, consultation, staff training and dedicated project coordination of up to 0.25 full-time equivalent (FTE) per year were also eligible.

Funded projects had to be monitored and evaluated. Each applicant proposed indicators suited to its project. At a minimum, each project had to survey local people on how they perceived its effects, covering perceived temperature, wildlife seen or heard, wellbeing and changes in use of the site. Project owners also committed to maintain the de-sealed areas over the long term.

Example: The Jean Macé school yard project in the commune of Narbonne de-seals 1,275 m² of a 2,190 m² yard used by 144 pupils, plants 1,200 m² and adds 11 trees. Before the works, the yard was mostly sealed and fully south-facing. The project disconnects part of the stormwater network and creates a cool, planted setting for learning on the model of the “cours oasis” (oasis school yard). Pupils and teachers helped shape the design through a workshop called “Imagine ta cour végétale” (Imagine your green yard).

Example: In the commune of Frontignan, the project converts the last 700-metre section of a former national road into a central urban boulevard. It creates about 3,500 m² of planted space and plants 40 trees. Ground planting uses Mediterranean species to limit watering, and the surfacing is permeable. An estimated 6,210 m² of sealed surface is disconnected from the stormwater network for small rain events.

The call was opened in 2022, on 1 January. It stayed open for five months. Applicants had until 31 May 2022 to submit either a short note of intent for a project still being defined or a full application.

An examination committee began work on 1 June 2022 and notified applicants of selection decisions by 30 September 2022. The call received 174 applications and selected about 40 projects.

Applicants selected with a ‘note of intent’ had one year from notification, and until 30 September 2024 at the latest, to submit a finalised funding application. Funding decisions were scheduled between September 2022 and December 2024.

Funded projects move into delivery after the grant award, with projects required to start within one year of award. Project owners remain responsible for maintaining the de-sealed sites and monitoring their effects. The delivery status of individual projects is unconfirmed.

The call delivers a priority of the Région’s water planning. In 2018 the Région adopted a Regional Water Intervention Plan (Plan d’intervention régional pour l’eau) with 21 priority actions. One of these commits the Région to reducing soil sealing and strengthening the soil’s capacity to retain water.

The Région has since prepared a new Plan Régional Eau (Regional Water Plan) after the severe drought of summer 2022. It was adopted in June 2023. The plan names de-sealing among the solutions it brings together to address a structural water deficit of about 200 million m³ in a normal year. It includes Challenge No. 31: supporting communes to de-seal urban soils. Source ↗

This project is led by the Région Occitanie, through the Ecological and Energy Transition Directorate (Direction de la Transition Écologique et Énergétique). The Directorate received applications and led the delivery of this program. The Regional Government managed the Secretariat for the examination committee which reviewed applications.

Two regional water agencies co-funded the call: the Adour-Garonne Water Agency and the Rhône Méditerranée Corse Water Agency. Applicants entered a single call with one examination committee. Each funded project then submitted funding applications to the Région and to a water agency, which assessed them under its own programme rules. The Rhône Méditerranée Corse agency’s 11th programme (“Sauvons l’eau !”, Let’s save water!) favours nature-based approaches over piped drainage. The Adour-Garonne agency’s 11th programme set a target of 1,000,000 m² of surface treated by the end of 2024.

The examination committee brought together the Région and the two water agencies. It could also include representatives of national government services and external experts.

The call implements regional, basin and national commitments:

• Regional Water Intervention Plan (2018). The call delivers its priority action on soils.
• Draft regional plan (SRADDET). The draft Regional Plan for Spatial Planning, Sustainable Development and Territorial Equality (Schéma Régional d’Aménagement, de Développement Durable et d’Égalité des Territoires) targets zero net artificialisation at regional scale by 2040.
• National law of 22 August 2021 on climate and resilience. It sets a national target to halve land consumption by 2031 and reach zero net artificialisation by 2050.
• River Basin Management Plans (SDAGE, Schéma Directeur d’Aménagement et de Gestion des Eaux) for 2022–2027.
• The Rhône Méditerranée Corse plan promotes de-sealing as a climate response (provision 0-01) and to reduce wet-weather pollution (provision 5A-04).
• The Adour-Garonne plan seeks to limit new sealing and de-seal existing surfaces (provision A31).
• Entente pour l’Eau (Water Agreement). The call contributes to the objectives of this agreement for the Adour-Garonne basin.
• National Stormwater Plan (Plan national Pluvial, 2022–2024). The call applies this national plan.

The call is a voluntary funding tool and carries no regulatory force. Where a project affects a river or wetland, the project owner must inform the local body responsible for aquatic environments and flood prevention (GEMAPI, Gestion des Milieux Aquatiques et Prévention des Inondations) at every stage.

A regional approach to water sensitive urban design

The Région set an overarching approach to water sensitive urban design (WSUD) for the whole of Occitanie. The call applied the same objectives in large urban areas, small town centres and rural areas:

• infiltrate rainwater where it falls
• disconnect stormwater from sewer networks
• reduce runoff
• bring nature into towns

Projects needed to address multiple priorities and achieve co-benefits, driving outcomes across integrated water management, heat mitigation and biodiversity improvement. This approach gave the Région a way to deliver a priority of its 2018 Regional Water Intervention Plan on land it does not own or manage. Projects delivered as a part of this call also contribute towards the delivery of the 2023 Plan Regional Eau.

The call brought together stakeholders with a direct interest in and mandate to reduce impervious surfaces for integrated water management outcomes.

Outreach

The call was published on the websites of the three funders. It was also relayed through existing networks that reach potential applicants:

• the Pyrénées catalanes Regional Natural Park
• Aides-territoires, the national government’s grants portal for local authorities
• Envirobat Occitanie, the regional network for sustainable building
• FREDON Occitanie, the regional plant health federation
• the Aqua-Valley water industry cluster
• the national federation of landscaping businesses

Sequencing

Occitanie delivered the call in the following order:

• It anchored the call in an existing regional plan priority.
• It agreed one set of rules with the two water agencies, covering objectives, eligible actions, aid ceilings and selection criteria.
• It published the call and relayed it through partner networks.
• It kept the call open for five months, from 1 January to 31 May 2022. Applicants could enter early with a short note of intent or submit a full application.
• A joint examination committee, with the Région as secretariat, assessed applications from 1 June 2022 and notified selections by 30 September 2022.
• Funding decisions followed project by project as each file was finalised. Each funder awarded its own grant through its deliberative body. The Région’s grants were voted by the Commission permanente, the Regional Council’s standing committee that approves grants. Its first four awards were made on 8 February 2023, and further awards were still being made in April 2024.
• Selected projects had until 30 September 2024 to finalise their applications.

The two-stage entry and rolling awards let less developed projects join the pipeline and mature over two years.

Demand exceeded the funds available. The call received about 180 applications and selected 41 projects, representing €16 million of planned studies and works.

The call grant funded a range of depaving and water sensitive urban design (WSUD) projects using funds from the Regional Government and two water agencies in the Region.

The water agencies fund their grants from levies on water use, under the principle « l’eau paie l’eau » (water pays for water). Every water user pays these levies according to the volumes they abstract or pollute. Households pay mostly through their water bills. The levies are collected and spent within each river basin. Each agency’s board sets a six-year programme of grants and loans to public and private bodies. This dedicated, ring-fenced water levy is the mechanism that allows the agencies to co-fund calls such as this one.

The call had an indicative budget of €8 million, of which €4 million came from the Région. The two water agencies’ individual contributions are not reported.

Grants covered at most 80% of a project’s eligible costs with a requirement for match funding at least 20% of an awarded project. Grants to private project owners, such as companies and developers, were adjusted under the European Union’s state aid rules, which limit public subsidies to businesses. Each project could receive up to €600,000 over 2022–2024, and projects had to cost more than €10,000.

Roughly 40 projects were selected:

• The Frontignan boulevard project cost €400,000 and received €142,830 from the Région and the Rhône Méditerranée Corse agency.
• The Narbonne school yard project cost €200,000 and was funded at 80% by the same two bodies.

Successful applicants carry the ongoing cost of maintaining their projects, and must commit to doing so and demonstrating funding for ongoing maintenance in their grant application. Funds could be used to support maintenance.

Co-Benefits & Trade-Offs

Flood risk reduction: increasing permeability slows run off and encourages water to filtrate through the ground, lowering local flood risk.

Quality of life: Replacing asphalt with planted spaces improves residents’ surroundings and makes town centres, streets and public spaces more attractive places to spend time.

Learning environments for children: Depaved school yards give pupils planted outdoor spaces for play, learning and contact with nature. About a third of all applications came from schools.

Community engagement and local support: The call required every project with works to include community engagement, so depaving became a visible local project as well as a drainage upgrade. Several projects involved children and families in the design.

Each project also had to survey local residents on how they experienced the changes, giving people a direct say in how results are judged.

Local action on regional goals: The call gave councils, schools and other landowners a practical way to act on regional targets for water, heat and land take. Applicants had to show how their project fitted their own wider policy on protecting soils and limiting new hard surfaces. This tied each site-level project to a local commitment beyond the grant.

Equity Considerations

The call’s outputs at selection are known, but no project results have been published. The call received 174 applications and selected about 40 projects. Of the selected projects:

• about one third de-seal school yards
• about one third redevelop town centres and urban spaces
• 10% de-seal car parks
• 10% rehabilitate brownfields and development zones

About 20 selected projects are in coastal départements, and 12 are local authorities close to lagoons with impacts for water quality and the health of marine environments.

• Pooling regional and water agency funding in one call, with one set of objectives and one assessment committee, gives applicants a single route to several funders.
• Requiring each project to show water cycle, sewer and cooling benefits together makes de-sealing a multi-hazard measure.
• Funding studies, coordination staff time and public awareness alongside works helps applicants with limited in-house capacity bring forward projects.
• A mandatory resident perception survey, with guidance on how to run it, builds evidence of how people experience de-sealed spaces, including perceived temperature.
• Requiring proof of land control and a costed maintenance commitment at application protects the long-term function of de-sealed sites.
• Opening the call to private landowners and companies extends de-sealing to land the public sector does not own.
• A two-stage entry through a short note of intent allows less developed projects to enter the pipeline.

The 41 funded projects are currently in delivery. The call supports the Région’s 2023 Plan Régional Eau, including its commitment to help councils remove impervious surfaces (Challenge No. 31).