This article reviews, illustrated by two case studies, how struggles around scales play out in three globally hegemonic trends in river governance: (1) stakeholder participation for (2) integrated water resources management (IWRM), conceived at (3) the watershed or river basin level. This ‘holy trinity’ has found blanket acceptance and support both in top-down (donors, governments) and bottom-up [nongovernmental organizations (NGOs)] directions as a way of democratizing water management, rationalizing water resource use, and managing conflict between water users in river basins. The precepts underlying these trends however have largely gone unquestioned, and the basin scale has become ‘naturalized’. This continuing hegemonic frame tends to obfuscate how boundaries are often manipulated for political ends and how different stakeholders frame the ‘natural’ scale in quite different ways. In this article we notably question the way boundaries get drawn and scales framed in light of water infrastructure, such as dams, canals, locks, and pipelines, which not only act as ‘pipelines of power’ but also seemingly impose management scale, ‘naturalizing’ water management in a different, semi-deterministic way. Rather than providing a full-fledged literature review, we build our argument drawing from cases from Ecuador and Turkey, each in its own way showing that depoliticizing discourse hides a political reality that may be better captured by ‘polycentricity’. WIREs Water 2014, 1:469–481. doi: 10.1002/wat2.1035 For further resources related to this article, please visit the WIREs website. Conflict of interest: The authors have declared no conflicts of interest for this article.