This paper focuses on the Guadalhorce Valley, Malaga Province, Spain, where a rich farmer-managed irrigation tradition has flourished since Arab times. Local communities diverted water from the river, managing numerous small-scale systems. These systems have now been destroyed. We trace the causes back to the profound impact that early twentieth century discourse about water control had on Spain's socio-natural landscape: an impact that extended far beyond water management. The idealistic Politico Hidroulica discourse, linked with 'regenerationism', glorified small-farmer irrigation and promoted hydraulic works and the expansion of irrigation as a socio-economic and cultural-political solution for Spain's bankrupt and 'degenerated' condition in the mid-19th Century. We follow the thinking and accomplishments of Rafael Benjumea, Count of Guadalhorce, Minister of Public Works and devoted follower of regenerationist leader Joaquin Costa. Benjumea was founding father of the widely acclaimed River Basin Confederations and one of Spain's chief 'hydraulic heroes'. We analyse the irony of the water policy discourse, the political paradoxes and conceptual contradictions of hydraulic utopianism. This political-ideological current aspired to install decentralized watershed management and defend local collectives' autonomy. Yet the policies, institutions and hydraulic works it established destroyed much of the local autonomy that did exist. The pursuit of the utopian project involved an iron-fisted, surgical policy of expertocracy, designed to restore 'natural order', which entailed overturning existing local water users' institutions, rights frameworks and knowledge systems. Analysing historical material and empirical data gathered during long-term field research on the Guadalhorce, we examine four bitter ironies of 'utopian hydraulism'. (C) 2012 Elsevier Ltd. All rights reserved.