This paper responds to a call to address the development and building of river-human relationships in the 21 ^st Century. Many literatures have identified the historical instrumental exploitation of natural resources underpinning urbanisation and the economic development of industry and society as leading to the wide-spread degradation of environments including rivers. Clearly such relationships can no longer be considered as appropriate in the 21 ^st Century. This paper intends to present a conceptual rethink to address the following question: Are there potential approaches by which humans can develop harmonious coexistent relationships with riverine landscapes and associated ecosystems? In answering this question, this paper draws on ideas from new materialism thinking. New materialism offers useful guidance in understanding human-river relationships in which river landscapes are not static backgrounds to the performance of the social. River systems and environments are active participants influencing and shaping social performances through multiple and diverse interconnected and complex human-nonhuman relationships and co-productive partnerships. It is concluded that new materialist perspectives provide important guidance for developing harmonious river-human relationships. De-centring the human as the dominant actor in relations with river landscapes and acknowledging rivers as key stakeholders within river-human relationships may enhance the building of harmonious coexistent and mutually beneficial relationships in the 21 ^st Century. It is further concluded the Nature Futures Framework (NFF) and Human-River Encounter Sites (HRES) frameworks in their capacity to accommodate new materialist thinking provide an opportunity for further exploration and examination of the possibilities for building harmonious coexistent river-human relationships.