Agricultural Irrigation Water Use in a Closed Basin and the Impacts on Water Productivity: The Case of the Guadalquivir River Basin (Southern Spain)

摘要

This paper analyses the agricultural irrigation water use in a closed basin and theimpacts on water productivity, and examines how they have affected the ‘closure’ process of theGuadalquivir river basin observed in recent decades. Following a period of expansion in irrigation,an administrative moratorium was declared on new irrigated areas in 2005. Since then, the mainpolicy measure has been aimed at the modernisation of irrigated agriculture and the implementationof water conservation technologies. The analysis carried out in this paper shows a significant increasein mean irrigation water productivity in the pre-moratorium period (1989–2005), driven by thecreation of new irrigated areas devoted to high value crops and with a dominant use of deficitirrigation strategies, while a second phase (2005–2012) is characterised by slower growth in termsof the mean productivity of irrigation water, primarily as a result of a significant reduction in wateruse per area. Findings show that productivity gains seem to have reached a ceiling in this riverbasin, since technological innovations (such as new crops, deficit irrigation, and water-saving andconservation technologies) have reached the limits of their capacity to create new value.