My interest in the use of groundwater for irrigation in Cusco led me to investigate the context in which this issue is discussed in the Andes. It is said that the water for the Tambo Machay canal comes from Lake Coricocha through an underground canal built by the Incas, this lake is also considered the source of water for several other rivers and irrigation systems. Although features of artificial underground channels are found in the Huatanay Valley, the connection between Coricocha and the Tambo Machay channel is neither natural nor artificial. There is simply no connection.

The two themes that stand out in this volume of Allpanchis are the analysis of technology within its socio-cultural context, and the incorporation of this analysis within a new policy for the development of the Andes. In pre-Hispanic times there was a wealth of complex and sophisticated technologies that are only recently being recognized: the dams, canals and cultivation under machaco en collo or tabla on the coast described by Antúnez de Mayolo; the irrigation systems in various areas of the sierra: on the western slope exposed by Gelles, in the Colca valley presented by Valderrama and Escalante and in the Inca Cusco described by Sherbondy; an underground drainage system in Inca Cusco that appears in Ardiles and the method for managing the lacustrine environments of the Altiplano by means of ridges or kurus present in Ramos's work.

This "new" interpretation of the ceque system is actually about ten years old. I came in August 1975 to do anthropological research on current irrigation in the department of Cusco. On that occasion I observed that various types of artificial irrigation systems were maintained at the same time, from projects carried out recently by the State to very old systems. What most caught my attention was a canal whose waters irrigated the lands of the Socsu-Aucaille ayllu in the town of San Sebastián, very close to the city of Cusco.