With more than 180,000 date palms, the Palmeral de Elche is the largest palm grove in Europe. In 2000, United Nations Educational, Scientific and Cultural Organization (UNESCO) declared a part of it aWorld Heritage Site. Actually, the Palmeral is a historic irrigation system with rows of palm trees flanking rectangular fields and serving as a windbreak and shade for the cultivation of wheat, alfalfa, fruit trees and vegetables. This system and its cultivation methods were mainly developed during the Islamic period and maintained after the Christian Reconquista in 1265 until recently. The main canal Acequia Mayor supplies irrigation water from the Vinalopó River which is then distributed through secondary canals to the different subsystems and fields as well as for domestic purposes. With an average slope of 1:260 (4‰) the main canal has a flow capacity of about 600 L/s. Owing to the topography, the canal must overcome a number of vertical drops where hydraulic energy must be dissipated. Beside the drop structures, at the same time watermills generate water power for flour production. These watermills have been built since the Islamic era and operated until the last century, when they were abandoned or converted for other uses. There are some descriptive publications and documents dealing with the mills, but there has not yet been any attempt to conduct a technical survey and interpretation. This study explores the remains of 11 watermills and determines the dimensions and technical parameters of this hydro-system. The mills were equipped with turbine-type horizontal waterwheels with hydraulic heads between two and more than 15 m. The observations allow conclusions on mill operation, power yield and flour production. A comprehensive description of this early example of waterpower generation in a multipurpose system is undertaken.