La variabilidad hídrica en la cuenca del río Atuel, desde la climatología histórica: siglo XVIII a mediados del XX

Since the mid-twentieth century, a conflict has developed on a national scale between the provinces of La  Pampa and Mendoza (Argentina), producing a so-called decrease in the amount of water from the Atuel river.  The main objective of the study is to try to reconstruct the hydrological conditions of Atuel river, from the  end of the eighteenth century to the mid-twentieth century and, in this way, analyze the claim of La Pampa  about the water volume reduction, attributed to the intensive agricultural use made by Mendoza, in the  middle basin. For this, a trend line of the Atuel river flows was created, using archival documents, traveler  stories, studies of naturalists, and military incursions, in which the pre-instrumental period is especially  considered. Subsequently, a comparison was made, based on reconstructions developed from other related  disciplines such as dendrochronology, glaciology, and meteorology. The results confirm that the Atuel River  presents a sustained decrease in its flow —although with pulses of floods and cyclical droughts— since the  end of the nineteenth century. In the observed pulses, important dry periods appear during the nineteenth  century, which even would have prevented that the basin flowed into its waters to the Colorado River, which  was supposed to be the normal situation before 1900. Main Ideas: Review article that proposes a hydroclimatic reconstruction of the Atuel river based on the analysis of historical documentation, contributing to the debate on the interprovincial conflict between Mendoza and La Pampa, and the research about the appropriation of water from “irrigated land” vs “deserts”.