Sustainable stormwater management at the Port of La Rochelle
- Giovanna Winetzki
- Sep 23
- 3 min read
Overview
At the Port of La Rochelle, the Lecamus shipyard buildings underwent major rehabilitation. The project aimed not only to modernize and extend the service life of the facilities but also to reduce their overall environmental footprint. Central to this ambition was a new stormwater management strategy: treating and infiltrating rainwater directly at the source to protect soil, groundwater, and the nearby Atlantic coast.
Challenge
The port environment presented constraints. Heavy vehicle traffic and industrial activities created a high risk of hydrocarbon contamination in stormwater runoff from roofs, roads, and parking areas. Previous reliance on a conventional hydrocarbon separator had not been sufficient to meet performance and sustainability standards.
Additional design factors included:
Soil conditions: the fill material in embankments was of poor quality, limiting the use of conventional infiltration systems.
Operational environment: although the site was not classified as an ICPE (Installation Classified for Environmental Protection), its industrial nature demanded robust protection measures.
Environmental impact: preserving local biodiversity and preventing hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) from reaching the ocean was a key requirement.
Both the project owner, Port Atlantique La Rochelle, and the project manager sought a solution that would be autonomous, long-lasting, and environmentally responsible.
Solution
The design office SIT&A Conseil specified OSMORIA® Geoclean aquatextile. Instead of diverting runoff through a separator and into networks, the solution integrated treatment and infiltration directly into the soil.
A buried granular basin was constructed, lined at the base and sides with nearly 1,000 m² of aquatextile. Rainwater collected from surfaces was routed to the basin, where it infiltrated through the aquatextile. OSMORIA Geoclean works through a dual mechanism: it optimizes and systematizes the fixation and biodegradation of hydrocarbons contained in the water that passes through it.
It fixes hydrocarbons to its filaments through adsorption (irreversible fixation), thereby preventing their migration into the subsoil. It then facilitates the biodegradation of the fixed hydrocarbon hydrocarbons and PAHs molecules. Unlike conventional absorptive materials, the textile’s matrix releases essential natural nutrients that attract and support native soil microorganisms, such as bacteria and fungi. These microorganisms multiply and accelerate pollutant breakdown, delivering consistent performance across diverse environmental conditions.
For example, laboratory trials with runoff water containing C10-C40 hydrocarbons at 30 mg/L showed a 99.9% retention and biodegradation rate, resulting in output concentrations below 0.03 mg/L. Additionally, the aquatextile has been shown to capture between 62% and 78% of PAHs, a fraction of hydrocarbons that are particularly harmful or even carcinogenic.
OSMORIA Geoclean is highly permeable, operated independently of soil quality, and required no maintenance.
The Lecamus shipyard rehabilitation demonstrated how ports and industrial sites could adopt innovative stormwater strategies that combined infiltration and depollution at source.
With OSMORIA Geoclean, Port Atlantique La Rochelle safeguarded its soils, groundwater, and coastline, while setting an example of sustainable infrastructure for other territories seeking to reduce impermeable surfaces and manage runoff responsibly.
Benefits
Protection of water quality: the presence of the aquatextile improves the retention and/or biodegradation efficiency of the C10-C40 hydrocarbon molecules studied by the infiltration device and also highlights the infiltration device's ability to manage pollution peaks with concentrations higher than the averages generally observed. (CEREMA, 2023)
Support for biodiversity: OSMORIA Geoclean aquatextile has a positive impact on soil biodiversity: “it has been shown to preserve almost all of the functional microbial diversity of soil ecosystems subjected to hydrocarbon pollution.” (Leesu, 2021-2022)
Restored water cycle: infiltration at source hydrates the soil and prevents network overload.
Conclusion
The Lecamus shipyard rehabilitation demonstrated how ports and industrial sites could adopt innovative stormwater strategies that combined infiltration and depollution at source. With OSMORIA Geoclean, Port Atlantique La Rochelle safeguarded its soils, groundwater, and coastline, while setting an example of sustainable infrastructure for other territories seeking to reduce impermeable surfaces and manage runoff responsibly.
