The aqueduct of Avre is one of the works which supplies the city of Paris with drinking water. Inaugurated in 1893, it carries 80 million liters (of a total of 680 million liters) per day. The water delivery is done by gravity: the altitude of the sources in the region of Avre is greater than 40 meters at the Montretout reservoir of St. Cloud, the point of arrival. Beyond Montretout reservoir, water is routed to the Paris metropolitan area. It crosses the Seine between St. Cloud and Boulogne-Billancourt, partly thanks to a structure built in 1891 by Gustave Eiffel , which is called the passerelle or bridge-aqueduct Avre.