The Montsouris Reservoir
This remarkable architectural structure is one of the five main drinking water reservoirs in the City of Paris (Montsouris, L'Haÿ-les-Roses, Saint-Cloud, Ménilmontant and Les Lilas) and is also one of the oldest. Built between 1869 and 1874 by engineer Eugène Belgrand in one of the highest spots in the south of Paris, it can hold more than 200,000 m³ of water and is fed by the Loing, Lunain and Voulzie springs located more than 100 km south of Paris, near Nemours and Provins.
It supplies the capital's lower water network (banks of the Seine) every day with the equivalent of 20% of the 480,000m3 of water consumed daily by Parisians.
The reservoir is above ground and is a large grassy mound surrounded by millstone walling. The vegetation helps keep the reservoir cool, while the presence of the wild plant and animal species that have been identified on the site also makes it a veritable urban reservoir of ecological potential within the Paris Green and Blue networks.
Inside the three stone pavilions decorated with blue mosaics and crowned with iron and glass roof lanterns, the water is collected and stored underground in vaulted galleries supported by 1,800 pillars, the largest of which are 7m high. The four compartments on two levels are completely independent of each other; each one has its own supply and outlet pipe in order to guarantee continued service in the event of a technical problem or maintenance.
Eau de Paris, an independent municipal body, manages the city's drinking water from production to transportation. Around half of the city's tap water comes from groundwater collected within a radius of 100 to 150 km (60 to 100 miles) around Paris. The other half is surface water from the Marne and the Seine rivers. Groundwater is processed in four plants built between 2004 and 2009, removing any traces of pesticides in the water. River water is treated in plants at Orly and Joinville. The water quality is constantly monitored at an analytical laboratory run by the municipal authorities, located in Ivry. On average, 500 million litres (132 million gallons) of drinking water are consumed every day in Paris, brought to the city's taps via 1 800 km (1,120 miles) of pipelines. Every year, Parisian tap water undergoes over a million quality checks. To preserve the quality of groundwater resources, Eau de Paris maintains uncultivated spaces above and upstream from catchment areas, as well as encouraging the development and continuation of organic farming, in order to improve water quality.
Inner Paris features nearly 580 hectares (1.433 acres) of gardens, parks and walks open to the public and managed by the City of Paris or by the State. Though fragmented throughout the most densely urbanised heart of the city, there are over 650 natural areas and green spaces. This fragmentation of habitats which are exploited by wild flora and fauna however is a major cause of decline in biodiversity. In addition to adapted management, the ecological potential of these spaces can be strengthened by reducing their fragmentation. This can be done by linking and promoting connections to the major ecological corridors crossing Paris, thus promoting movement between these inner city spaces and more remote biodiversity reserves. The creation of a map of the green and blue corridors within Paris will ensure the effectiveness and consistency of these projects. This document will guide the creation of new parks and gardens as well as a network of uncultivated urban land not accessible to the public.
The Seine, the canals and all the artificial wet zones - lakes, ponds, fountains and ornamental ponds - constitute the Parisian blue network: a system conducive to the development of aquatic flora and fauna, and strengthening biodiversity through a dynamic connection between different locations. So the Biodiversity Action Plan plans considers creating 40 new wet zones before 2020.