Cartographie des anciens cours d’eau, lignes de creux et des bassins versants de l'île de Montréal
The cartography of the island of Montreal's former watercourses is lacking and must be redone in the most documented and transparent way possible. Two maps are currently used as references: "Carte topographique de l'île de Montréal de 1542 à 1642" [Topographic map of the island of Montreal from 1542 to 1642], drawn around 1930 by architect and researcher Aristide Beaugrand-Champagne, for which sources were not provided, and which contains numerous hydrographic incoherencies; and "Montréal - Ruisseaux et fossés" [Montreal - Streams and ditches], drawn by the Eaux et Assainissement [Water and Sanitation] division of Montreal’s Public Works Department in 1958, which covers part of the island, and for which some of the sources referenced have disappeared from the city’s archives.  A new survey of the island's watercourses has been undertaken by the team of Valérie Mahaut, assistant professor at the school of architecture of the Faculté de l’aménagement, Université de Montréal. After consulting more than one hundred original historical maps, some thirty were selected, geolocalized, and plotted; they form the core of the compilation work conducted in this study. From this data, several new maps were produced and made available online for free to serve as references for various disciplines and users. This surveying work is merely the first step in a broader project which promotes integrated rainwater management in urban areas. The data collected was interpreted so that the maps produced also show the thalwegs and crest lines (ridge lines or watershed boundary lines) of the island of Montreal's former watercourses with the goal of establishing "New Urban Rivers".
Montréal thalweg crest line ridge line watershed watercourses stream ruisseaux hydrography topography altimetry historical map mapping cartography