Spain is arguably the European country where the water crisis has become most acute in recent years. The political and ecological importance of water is not, however, only a recent development in Spain. Throughout this century, water politics, economics, culture, and engineering have infused and embodied the myriad tensions and conflicts that drove and still drive Spanish society. And although the significance of water on the Iberian peninsula has attracted considerable scholarly and other attention, the central role of water politics, water culture, and water engineering in shaping Spanish society on the one hand, and the contemporary water geography and ecology of Spain as the product of centuries of socio-ecological interaction on the other, have remained largely unexplored. The hybrid character of the water landscape, or “waterscape”, comes to the fore in Spain in a clear and unambiguous manner. The socionatural production of Spanish society, I maintain, can be illustrated by excavating the central role of water politics and engineering in Spain’s modernization process. In the first part of the paper, I develop a theoretical and methodological perspective that is explicitly critical of traditional approaches in water-resources studies, which tend to separate various aspects of the hydrological cycle into discrete and independent objects of study. My perspective, broadly situated within the political ecology tradition, draws critically from recent work by ecological historians, cultural critics, sociologists of science, critical social theorists, and political-economists. My main objective is to bring together what has been severed for too long by insisting that nature and society are deeply intertwined. In the second part of the paper, I excavate the origins of Spain’s early-twentieth-century modernization process (1890-1930) as expressed in debates and actions around the hydrological condition. The conceptual framework presented in the first part helps structure a narrative that weaves water through the network of socionatural relations in ways that permit the recasting of modernity as a deeply geographical, although by no means coherent, homogeneous, total, or uncontested project. In sum, I seek to document how the socio-natural is historically produced to generate a particular, but inherently dynamic, geographical configuration. © 2007 Lavoisier, Paris. Tous droits réservés.