At the Festival du Monde, a dive into the Austerlitz storage pool | EUROtoday

“It is the first time that this emblematic pharaonic work of the Paris 2024 Olympic Games has been open to the public! »»exclaims Stéphane Mandard, journalist in the newspaper’s planet service The world. Friday, September 19, as part of the festival organized by the daily, the latter guided around twenty readers to discover the Austerlitz basin, this reservoir is intended for “Protect the city from potential overflows of the Seine” and to clean up the river. A capacity of 50,000 m³ (the equivalent of 20 Olympic swimming pools), the basin must, in the event of strong showers, store part of the wastewater that the old sewer network of the capital poured into the Seine when it is saturated.

First stop of the course, an underground hatch, sheltered from urban traffic and located between Square Marie-Curie (13^e Arrondissement) and the air metro of line 5. In front of this hatch, leading to stairs, the excitement rises from a notch. Nicolas Londinsky, head of the Technical Water and Sanitation Service to the City of Paris brings the participants to the bowels of this underground cathedral, located several meters underground, descended.

In a cooler temperature than in surface, the group finds itself immersed in a concrete room, a labyrinth pipes of all sizes lines the walls. A large map of the Paris sanitation network dresses a bare wall of this first large room. Some photos of the construction of this titanic project are also exhibited there. Fruit of four years of work, before its inauguration in June 2024 for the Olympic Games, this work is now finished.

Potician statistician

Visitors discover a tank Make up to 34 meters deep and its giant concrete pillars. A strong smell of humidity permeates the place. “Is it reinforced concrete?” »» Question some participants while tiering to try to see the substance. “It is a unique chance here to see the complexity of water management in the city of Paris”says an architect of retired treatment plants.

“We do not treat water. What fits into this basin is worn water and what comes out is always worn water ”specifies Etienne Kleitz, Engineer answerable for the challenge, properly wanted by the curiosity of the members on the origin of this water saved right here. “In this basin, rainwater and wastewater (coming from domestic use) mix there ”, explains Etienne Kleitz.

Passionate about water subjects, Claude (who did not wish to give his last name), 70 years old, holds an Excel file in which he has noted every day for five years “The water movement from Austerlitz and the 4 lakes upstream of the Seine basin”like a pointed statistician. “I’m all for selections which are made to keep away from floods”explains this former bank employee.

“Not but very serene”

After an hour and a half, the group dates back to daylight with the gigantism of this underground project in mind. Thomas, 22, wanted to discover “The technical means put in place to scrub up the Seine”. This student studies themes related to the environment and the marine environment. “Seine’s sanitation investments for thirty years have improved water high quality and enhance the number of fish noticed as much as fifty”explains journalist Stéphane Mandard.

Perrine, also 22 years old, entrusts a more personal motivation: “I would really like to have the ability to bathe within the Seine, even when I’m not but very serene”she says smiling. In front of the quasi summer weather this Friday in September, some took their jerseys hoping for a small bath in the river. The swimming, on the Bercy side, officially end this Sunday, September 21. Then it will be necessary to wait until 2026 For the next dives.