We define and explore hydrosocial territories as spatial configurations of people, institutions, water flows, hydraulic technology and the biophysical environment that revolve around the control of water. Territorial politics finds expression in encounters of diverse actors with divergent spatial and political-geographical interests. Their territory-building projections and strategies compete, superimpose and align to strengthen specific water-control claims. Thereby, actors continuously recompose the territory’s hydraulic grid, cultural reference frames, and political-economic relationships. Using a political ecology focus, we argue that territorial struggles go beyond battles over natural resources as they involve struggles over meaning, norms, knowledge, identity, authority and discourses.

This article provides a framework for understanding water problems as problems of justice. Drawing on wider (environmental) justice approaches, informed by interdisciplinary ontologies that define water as simultaneously natural (material) and social, and based on an explicit acceptance of water problems as always contested, the article posits that water justice is embedded and specific to historical and socio-cultural contexts. Water justice includes but transcends questions of distribution to include those of cultural recognition and political participation, and is intimately linked to the integrity of ecosystems. Justice requires the creative building of bridges and alliances across differences.

Mega-damming, pollution and depletion endanger rivers worldwide. Meanwhile, modernist imaginaries of ordering ‘unruly waters and humans’ have become cornerstones of hydraulic-bureaucratic and capitalist development. They separate hydro/social worlds, sideline river-commons cultures, and deepen socio-environmental injustices. But myriad new water justice movements (NWJMs) proliferate: rooted, disruptive, transdisciplinary, multi-scalar coalitions that deploy alternative river–society ontologies, bridge South–North divides, and translate river-enlivening practices from local to global and vice-versa. This paper's framework conceptualizes ‘riverhood’ to engage with NWJMs and river commoning initiatives. We suggest four interrelated ontologies, situating river socionatures as arenas of material, social and symbolic co-production: ‘river-as-ecosociety’, ‘river-as-territory’, ‘river-as-subject’, and ‘river-as-movement’.

Locally and globally, mega-hydraulic projects have become deeply controversial. Recently, despite widespread critique, they have regained a new impetus worldwide. The development and operation of large dams and mega-hydraulic infrastructure projects are manifestations of contested knowledge regimes. In this special issue we present, analyze and critically engage with situations where multiple knowledge regimes interact and conflict with each other, and where different grounds for claiming the truth are used to construct hydrosocial realities. In this introductory paper, we outline the conceptual groundwork. We discuss ‘the dark legend of UnGovernance’ as an epistemological mainstay underlying the mega-hydraulic knowledge regimes, involving a deep, often subconscious, neglect of the multiplicity of hydrosocial territories and water cultures. Accordingly, modernist epistemic regimes tend to subjugate other knowledge systems and dichotomize ‘civilized Self’ versus ‘backward Other’; they depend upon depersonalized planning models that manufacture ignorance. Romanticizing and reifying the ‘othered’ hydrosocial territories and vernacular/indigenous knowledge, however, may pose a serious danger to dam-affected communities. Instead, we show how multiple forms of power challenge mega-hydraulic rationality thereby repoliticizing large dam regimes. This happens often through complex, multi-actor, multi-scalar coalitions that make that knowledge is co-created in informal arenas and battlefields.