ROJAS Juan Facundo
congresos y reuniones científicas
Climatic variations in the Cordillera de los Andes and their consequences for environmental processes in northern Mendoza from the 16th. to 20th. centuries
Workshop; Documenting, understanding and projecting changes in the hydrological cycle in the American Cordillera, Final Science Meeting: IAI CRN 2047.; 2011
Institución organizadora:
Inter-American Institute for Global Change Research
Environmental Processes in northern Mendoza from the 16th. to 20th. CenturiesMaría del Rosario Prieto and Facundo RojasUnidad de Historia Ambiental, IANIGLA-CONICET-MENDOZA;Keywords: climatic variations, environmental processes, wetlands, Northern Mendoza OasisThis paper examines changes in the area between the 16th and 20th centuries of the GranCiénaga del Bermejo, a major wetland area north-east of Mendoza City, based on old mapsand documentary sources. These changes reflect variation in the flow of Rio Mendoza andAndean snowfall plus the impact of drainage schemes associated with agriculture. Prior to the18th century these wetlands were relatively small but they expanded rapidly in the areanortheast of the city of Mendoza due to dramatic and progressive increases in flow of RíoMendoza at the turn of the 18th century. The wetland area occupied a large part of the lowestzones of the Mendoza oasis as a result of this increased runoff plus soil saturation due to a riseof the water table. This situation continued through the 19th century, affecting the extensionand use of the available land for human activity. This increase in area culminated in 1930when partial desiccation of the wetland resulted from strong human impact (drainage), despitethe wet years of 1926 and 1930. However, in wet years there remain problems with soildrainage.Our studies have focused on the influence of climatic fluctuations in the Cordillera and theconsequent variations of the flow of Rio Mendoza as they effect changes in the wetlands. Wehave utilized proxy records of snowfall series in the cordillera and flows of the Rio Mendoza,developed by Prieto (2009) from documentary data. We have analyzed the long and shortterm consequences of the growth and later desiccation of the wetlands on the surroundingenvironment and the contemporary repercussions on the ecosystem (salinization, poor soildrainage, soil alkalinization). In addition, we have also developed and used georeferencedhistoric charts to show the behavior of the Cienaga del Bermejo during the 18th, 19th and 20thcenturies. This behavior is characterized by growth pulses and retraction phases that can beseen on the analyzed charts. Periods of major growth coincide with times of bigger snowpackand larger flow volume in the Rio Mendoza.