Riparian systems as boundary objects in sustainable water transition

This paper contributes to debates on sustainable transitions in urban water management by proposing a relational and governance-oriented understanding of river-city interactions. It argues that the sustainability of these interactions does not evolve through discrete socio-technical phases, but rather through overlapping and uneven governance domains that reflect shifting legal, ecological, and political relations. Drawing on political ecology, the paper mobilises the concept of boundary objects to rethink rivers not simply as components of socio-technical systems, but as entities that enable coordination across heterogeneous actors, knowledges, and values, including multispecies concerns. We illustrate this argument through the San Pedro River basin in the metropolitan region of Quito, Ecuador. In this context, the riparian system emerges as a boundary object that challenges dominant urban water regimes by intertwining diverse human actors (laws, municipalities, industries, agricultural sectors, and civil society) with non-human actors such as livestock, microorganisms, and scavenger species. Through this lens, sustainable transitions appear as gradual, multidimensional reconfigurations of governance and justice, rather than as linear transformations of technical systems.