Cemex is playing a key role in one of Paris’s most ambitious infrastructure upgrades—a massive underground water basin designed to safeguard the Seine River.

As part of the Austerlitz storage basin project near the Gare d’Austerlitz railway station, Cemex has supplied 30,000 m³ of high-strength concrete and transported over 128,000 tons of excavated material by river barge, supporting efforts to dramatically reduce wastewater discharge during rainstorms.

“We are proud to participate in this ambitious infrastructure project that will help prevent wastewater discharge from reaching the River Seine,” said José Antonio Cabrera, President of Cemex Europe, Middle East & Africa. “Cemex remains at the forefront of developing building materials for large-scale projects, contributing to a positive impact in urban areas such as Paris.”

The Austerlitz Basin, a cylindrical structure measuring 50 meters wide and over 30 meters deep, can store more than 50,000 m³ of stormwater—roughly the volume of a dozen Olympic-sized swimming pools. During periods of heavy rain, underground tunnels and collector wells divert runoff into the basin, preventing it from overwhelming the city's wastewater system and spilling into the Seine. Once the storm passes, the water is routed to a treatment plant before being released safely back into the river.

This marks a significant environmental improvement for Paris, where, historically, combined sewer overflows would lead to untreated water entering the Seine—a problem the city is racing to fix ahead of the 2024 Summer Olympics, during which parts of the river are expected to host aquatic events

Sustainable Logistics by Water

Cemex’s role in the project went beyond material supply. To reduce traffic congestion and emissions, the company coordinated the transport of construction and demolition materials by barge, utilizing the Seine’s inland waterway network. Materials were shipped to Cemex facilities in Normandy and locations north of Paris, where they were sorted and processed, supporting circular economy goals.

An Olympic Legacy in the Making

Paris’s multi-year effort to clean the Seine is one of the capital's flagship sustainability projects, part of a broader urban resilience strategy. By constructing the Austerlitz Basin and other overflow basins, city officials hope to make the Seine safe for swimming by 2025—something not achieved in over a century.

Cemex’s Green Focus

The project aligns with Cemex’s mission to support sustainable urban development. The company is actively working toward carbon neutrality, investing in alternative fuels, recycled materials, and low-carbon concrete technologies across its global operations.

With projects like this, Cemex continues to demonstrate how modern building materials and smart logistics can power large-scale environmental change in dense, historic cities like Paris.

Originally reported by CEMEX.