Hydraulic technology as means of Christian colonisation. Watermills and channels in the Lower Ebro (Catalonia)

In this study, evidence provided by written records generated after the conquest of Tortosa in 1148 and the results of archaeological survey have led to the identification of several farmland areas and their associated Andalusi settlements on both banks of the River Ebro, in the hinterland of Madīna Ṭurṭūsha. These field systems were formed by compact and discontinuous cultivation areas on the riverbanks. Drainage channels and wells with water-lifting wheels comprised the main hydraulic techniques used. One of the most relevant changes as a consequence of feudal conquest was the introduction of new hydraulic systems consisting of water catchment in the hills above the river and long channels, whose main purpose was to drive watermills. These channels were rather complex in terms of technology and distinct from those of the Muslim peasant tradition and we can recognise the political power behind them.