Aguas, riego y cultivos: Cambios y permanencias en los Ayllus de San Pedro de Atacama

Abstract

Water has been an essential factor in the historical development of the Ayllus of San Pedro de Atacama, irrigated by the San Pedro and Vilama rivers. The amount of water carried by these rivers has been diminishing since the 1940s, which has forced successive changes in the cultural practices of water use and management in order to ensure irrigation and to sustain an agriculture based on traditional crops - maize, wheat and alfalfa. This article uses statistical data to demonstrate the ongoing reduction of the average yearly flow rate of these rivers over the last seventy years, changes in the irrigation system and infrastructure, and the successive organizational changes that have occurred to manage this scarce hydrological resource in a desert environment. The analysis reveals that over the last forty years the irrigated and cultivated surface area has reduced almost 50%, paired with the reduction in the hydric contributions of the San Pedro and Vilama rivers. This article also showthat the traditional crop structure has been maintained until recent years and explores whether the present balance between water supply, irrigation and crops is sustainable over time in the Atacama's ayllus.