Remaking land–water boundaries in the Rhone plain in Switzerland: A reinterpretation of past and present river training using a ‘postcolonial mirror’

River training in Europe has recently shifted from a focus on hard infrastructure toward river widening and renaturation. Inspired by postcolonial studies on land–water dichotomies, this article seeks to examine the material and ideational remaking of land–water boundaries through past and current river interventions on the Rhone River in the Valais, Switzerland. Based on an analysis of historical and contemporary documents, we show how the first two major river projects between the mid-19th and mid-20th century led to a gradually increasing separation of land and water. The current river-training project gives more space to the river, but it deepens the land–water demarcation through reinforced flood protection. Using a ‘postcolonial mirror’, a heuristic tool to uncover ontologies, discontinuities and continuities across space and time, we then identify the historical continuities of different forms of domination of the river, ranging from scientific knowledge and conceptualizations to commodification and the creation of false memories. We conclude that the colonial mirror is a useful heuristic tool to uncover usually hidden processes.