A determined expansion in the productive capacity of Spanish agriculture was a fundamental and contentious objective during the crisis of the country’s ancien régime and the formation of the liberal state, in the years of transition from the eighteenth to the nineteenth centuries. In this study we examine a fundamental reorientation that occurred in an ambitious project for the expansion of irrigation in the region of Valencia. In this region, characterised by a well-rooted commercial agriculture, the original scheme, initiated by an enlightened aristocrat well connected with the royal court, would be profoundly altered in the transition from one political regime to another. The irrigated area increased much more than had been anticipated, and very diverse sections of the social hierarchy eventually benefited from this agricultural expansion. In contrast, the control exercised over the irrigation canal by the aristocrat himself would be increasingly questioned in the context of the nineteenth century.