This article examines how Santiago’s modernisation — specifically, the channelling of the Mapocho River under Vicuña Mackenna’s rule — transformed the river’s role in the city’s collective imagination, how it evolved from being perceived as a simple waterway to a border and heterotopic space, deeply intertwined with the city’s socio-spatial fabric. Using Michel Foucault’s notion of heterotopia, the political narratives surrounding Santiago’s modernisation and their spatial impacts are analysed through the lens of the novel El Río by Alfredo Gómez Morel. The research traces the development of fluvial imaginaries that shaped the Mapocho River in the early 20th century, incorporating urban, social, and environmental changes at the century’s turn. As a result, the river emerges not only as a geographical feature but also as a symbolic space, rich with meanings that have been influenced by Santiago’s shifting social and cultural needs. Ultimately, the study explores how these representations contributed to the Mapocho’s material and imaginary construction, creating a dynamic interplay between the river and its evolving context.

fluvial imaginariesMapocho riverborderlandheterotopiamarginality