From Old Wells and Watercourses of the Island of Manhattan, by George Everett Hill and George E. Waring, Jr. in Historic New York: the First Series of the Half Moon Papers (New York, 1899):
Around this ditch gathered much of the social and business life of the new community....
mid-19th century map showing the original lots of the Dutch settlement
in the 17th century shows both the marsh and the Broad St Canal (first
image is entire map, second image is close-up). Note how close Broadway
("The Great Highway") is to the Hudson ("The North River"); almost all
the land west of Broadway at the south end of Manhattan is landfill.