How to analyze the coexistence of, on the one hand, a diversity of doctrines and devices for public action, and, on the other, trends towards standardized norms, ideologies and sources of expertise concerning water management? How to grasp the manner waterscapes are being framed and governed? How do scientists and the scientific claims they produce concerning water interact with politically and historically loaded territories? How are defined what is given and what is not, what are the relevant boundaries, criteria and knowledge to define and handle a specific problem? How are produced environmental and social categories around water? Based on the analysis of the Garonne system (southwestern France), we will study the manner scientists may, or not, find human or non-human allies deeply rooted in territories to produce knowledge that becomes a situated resource strengthening specific coalitions of actors and/or a claim circulating widely. We will also show the manner the historical trajectory of rivers, of their related social practices and power relations deeply influences the scientific disciplines that are selected or discarded and the epistemology of their spokespersons (Fernandez 2013, Fernandez & al. 2014). To conclude, we will put the Garonne case into perspective (Bouleau & Fernandez 2012), to show that some places are more conducive to the development of some ideas and how these ideas also impact landscapes.