Aménagements portuaires

Rehabilitation project of the banks of the Marne upstream of the port of Bonneuil-sur-Marne

- Direction territoriale de Paris

Published on

Situation of the project within the port of Bonneuil

Commercial navigation of the port of Bonneuil takes place in both port docks, while the Marne has natural banks offering ecological and landscape qualities to be preserved and improved.

In 2003-2004, Ports de Paris carried out a restoration operation on the left bank of the Marne, downstream of the Bonneuil Bridge. This 600 linear metres of development has brought a clear added value to the environment, both ecological and landscaped: erosion stopped, biodiversity in progress.

Dans le cadre de sa politique de responsabilité sociétale et environnementale, et en application du schéma d’aménagement et de développement durable (SADD) du port de Bonneuil-sur-Marne, HAROPA - Ports de Paris a élaboré un projet comparable de réhabilitation écologique de la Marne sur les berges amont sur un linéaire de 850 mètres, entre le viaduc du RER A et le pont de Bonneuil.

As part of its policy of social and environmental responsibility, and in applying the growth and sustainable development plan (GSDP) of the port of Bonneuil-sur-Marne, HAROPA - Ports de Paris has developed a comparable ecological rehabilitation project for the Marne on the upstream banks over a length of 850 metres, between the RER A viaduct and the Bonneuil Bridge.

Objectives of the project to rehabilitate the banks of the Marne upstream

The left bank of the Marne upstream of the port of Bonneuil suffers from erosion under the effect of wave action. The slope has become weakened as a result. From a landscape point of view, this bank is in an abandoned state, as it is located at the bottom of the plots of the port's farm owners. Vegetation is developing there spontaneously: we see the ageing of the tree formation, the arrival of invasive alien species. As a result, the potentially interesting ecological quality of the site remains low.

The aim of the rehabilitation project is to stop these degradation phenomena and enhance the assets of this site, a breathing space in a dense urban environment. The development therefore plans to restore ecological environments, stabilize the riverbank slope, improve the landscape qualities of the banks of the Marne, and finally offer the public the opportunity to walk along the bank while respecting the areas dedicated to the development of local biodiversity.

Description of the planned developments

> Ecological restoration and slope stabilization

 The development project will reintroduce a variety of environments that promote biodiversity from the foot of the slope to the bank crest. Thus, the interventions will be carried out by plant techniques or by mixed civil and plant engineering techniques. This consists in planting plants adapted to the different levels of the shoreline to maintain it by the root systems, eventually introducing riprap to consolidate the whole. Reducing erosion will also be achieved by softening the bank slope, which will have the additional positive effect of widening the riverbed and providing more room for flood expansion. On part of the shelf, the bank profile will not be modified and only plant sanitation operations will be carried out to remove diseased or invasive plants.

> Improving the accessibility of the shoreline and landscape qualities of the site
 The crest of the riverbank will accommodate a pedestrian walkway within better maintained and better structured vegetation. As priority is given to developments that promote biodiversity, this route will be narrow and will not allow access to the foot of the riverbank directly onto the water. The possibility of closing access to the path during the night will be studied in order to minimize wildlife disturbance. Reflection is given to the landscape architect and consultant of the port of Bonneuil to combine this ecological project with architectural interventions on the rear facades of the buildings located along this bank, in order to improve their integration.

The project is supported by a grant from the Île-de-France Region and the Seine-Normandy Water Agency.

Regulatory approvals

The rehabilitation of the banks upstream of the port of Bonneuil is subject to authorization under the Water Act. The project was therefore submitted to the Environmental Authority for an opinion in 2015. A public survey was conducted in 2016. The Board of Directors of HAROPA - Ports de Paris then voted on a resolution declaring the project to be of general interest. At the end of the procedure, in January 2017, the project was authorized by prefectoral decree.

Find the main documents related to the regulatory procedure:
 - Environmental Authority opinio,
 - investigating commissioner's report,
 - project declaration,
 - prefectoral decree.

Progress of the work (October 2018 - February 2019)

To minimize the impact of the site on the fauna and flora, the prefectoral decree requires that the work takes place between September and March, because it is the rest period for vegetation, which is more conducive to the recovery of the planted plants.
 Work will therefore resume from October 2018 to February 2019, for a first section between the RER A viaduct and the Hamlet of Moulin Bateau. The second section between the Hamlet of Moulin Bateau and the Bonneuil Bridge will be dealt with in the winter of 2019-2020. It is indeed necessary to limit the fragmentation of interventions in space under penalty of having to manage transitions between several sections which constitute potential weaknesses of the developments.

The work will consist of:
- general earthworks to ensure the reprofiling of the bank and the few necessary embankments, the development of shoals, the construction of rockfill at the foot of the bank;
- civil engineering: cutting of sheet piling, creation of a mooring pontoon and a launching ramp at the restaurant La Caravelle;
- plant and forest engineering: creation of bank tusks (helophyte fascination, plantations...), bank vegetation cover, shrub and tree planting work;
- road works: creation of a path between the restaurant La Caravelle and the Bonneuil Bridge. In the direction of the RER viaduct, the route will be transferred to the pavement of the Brétigny road, due to the narrowness of the land available along the river bank. Thus, the connection will be ensured with the Bec de Canard, another sector in which HAROPA - Ports de Paris is working on an ecological restoration and educational enhancement project.

Project stakeholders:
- HAROPA - Ports de Paris, Agence Seine-Amont, is responsible for project management and project ownership. To contact us:; 01 43 39 02 50;
- Egis has the role of technical assistant to the project owner;
- ETPO intervenes on the banks: earthworks, reprofiling, implementation of civil engineering techniques to fix the reprofiled banks on the sections concerned;
- ID Verde carries out the planting work: plant engineering techniques on the affected sections, plant sanitation, landscaping along the route;
- Au fil de l'eau (integration association) should be associated with part of the plant development and will be mobilized for the subsequent maintenance of this bank;
- Colas creates the path;
- Environnement Services works on fences, some of which are to be moved and others created;
- A security coordinator will be assigned in the coming weeks;
- Urbicus, consultant architect of the Ports de Paris, creates sketches for improving the architectural quality of the building façades overlooking the riverbank;
 - Alter & Go Concertation facilitates communication around the project.

Reminder of the main commitments made at the end of the public inquiry in June 2016

- The trees
 During the public inquiry, concerns were raised about the disappearance of the vegetative screen of trees in relation to industrial buildings.
 In response, HAROPA - Ports de Paris reminds us that the project is designed to consolidate the bank weakened by erosion, a phenomenon accentuated by the growth of certain trees planted in the slope. During the execution of the work, the remarkable trees identified will be preserved. The trees will be replanted exclusively at the top of the slope to diversify living conditions on the different bank floors and promote the biodiversity typical of the banks of the Marne. The strength of the replanted subjects will result from a compromise between, on the one hand, the desire to plant trees sufficiently developed to improve the landscape qualities of the site, and on the other hand, the need to plant trees young enough to maximize the recovery rate and avoid significant losses. The balance of trees removed and replanted has been adjusted following developments since 2016.

- The pedestrian path
 The questions asked during the public inquiry highlighted the fear of noisy occupation and degradation on this path.
 For HAROPA - Ports de Paris, the small size of the path will not encourage problematic traffic (for residents but also for companies located just next door) while making it possible to respond to a request to open the port to the cities, particularly Bonneuil-sur-Marne, and by offering a quality walking space to the platform's employees. In order to reduce the risk of disturbance, HAROPA - Ports de Paris is currently studying the possibility of closing access to the route in the evening.