Did you spot the grassy hill? That green space hides a secret. It conceals the Tour du Réservoir. This isn’t just any reservoir. The Tour du Réservoir stores drinking water for about 20% of Paris.
Let’s dive into the story of this vital structure. Imagine Paris in the 19th century. The population boomed. The Seine River became too polluted for drinking. A new solution was needed. Enter the Tour du Réservoir de Montsouris. Construction spanned from 1868 to 1873. It was designed to collect water from cleaner sources. Aqueducts from the Aube and Seine-et-Marne regions fed the reservoir. These included the Vanne, Loing, Arcueil, and Cachan aqueducts.
The Tour du Réservoir has a fascinating design. It features two levels of reservoirs stacked on top of each other. Each level is divided into two sections. The upper reservoirs are about 3.3 meters deep. The lower ones reach 5 meters. Overall, the structure is 265 meters long and 135 meters wide. It holds a massive 202,000 cubic meters of water. That is a lot of water.
Now, for a quirky detail. Until 1996, the Tour du Réservoir used truites to test water quality. Aquariums with truites connected to the water supply. Healthy truites meant clean water. It was an early warning system. Modern scientific methods replaced this system. Labs now handle the water testing.
Above the Tour du Réservoir lies a layer of earth. This helps maintain a cool, stable temperature inside. The grassy area on top could become a local farm one day. Fresh fruits and vegetables might grow there.
Beneath the reservoir are old quarries. These quarries are part of the Grand Réseau Sud de Paris. People know it as the Catacombs of Paris. Workers consolidated the quarries to support the Tour du Réservoir. This created a network of tunnels under the structure. These tunnels have a spiral staircase leading to the surface.
The Tour du Réservoir may not be a classified historical monument. Yet, it is an architectural marvel. It combines underground tunnels, water reservoirs, and a green rooftop. Together, they form a unique layered structure. The Tour du Réservoir plays a crucial role in keeping Parisians hydrated. The five main reservoirs meet the daily need of approximately 600,000 m3 for the inhabitants of Paris.
Next time you take a sip of water in Paris, remember the Tour du Réservoir. It is a hidden gem. It keeps the city flowing.