Introduction This chapter examines the role of scientific development and analyzes the determinants of irrigation dynamics in the policy debate of water for food. Reviewing and compiling hitherto unexplored data, we make a case for improving upon water availability to the farm sector. The critical assessment of the role of these determinants on future rural landscapes and societies may provide information for future policy development. The last 20 years have seen a major change in the way Spanish society perceives water problems. The perception that in all cases water for food competes with ecosystems and urban uses has been nurtured in the course of a number of high-impact environmental extremes (e.g. 2001-2005 drought), high profile organizations – both public and private – and international policy debates of high-profile (e.g. biofuels and climate change). Deeply ingrained in the mentality of economists and the general public is the view that scarcity periods are exacerbated by water agricultural use (Estevan and Naredo 2004). Furthermore, the notorious controversies between the Ministries of Agriculture and of Environment during the 2004-2008 political term have added fuel to the adversarial views between farmers and the environment. Irrigation in Spain has evolved for more than 12 centuries, but modern irrigation has progressed rapidly in the last 50 years, making a transformation (silent evolution) of population settlement on landscapes that otherwise would not really support large numbers of people, due to the aridity of the climate. Between 1950 and 1975, Spain doubled the irrigated acreage and built around 1,000 new big dams, which is a material reflection of the priorities of Franco’s governments under his 40-year rule. More recently, the European Union’s Common Agricultural Policy was from 1986 until 2003 a fundamental driver of farmers’ decisions. Farm support programs evolved from strong price support mechanisms to almost fully decoupled direct payments. This gradual change has interacted with two other recent policies: national water policy and the EU Water Framework Directive. In 2008, the prospective of irrigated agriculture changed entirely as a result of the global tensions of basic commodity prices.