Analysis of the effect of El Niño and La Niña on Tecocomulco Lake, central basin, Mexico

Abstract

Tecocomulco Lake is a relic of the great basin of the central plateau of Mexico. Its surface area changes in response to both the variation in the inputs from inland areas and the effects of the climatic phenomena of El Niño and La Niña. It is endorreic, with a low rainfall and a low and intermittent fluvial input, a high evaporation, and a considerable influx of sediment due to deforestation and a bad management of the basin. The most important plant species is Schoenoplectus californicus that grows massively in muddy areas, decreasing the depth and reducing the flooded area. The lake is visited by birds from USA and Canada, that arrive to nest and reproduce. During the extremely dry years that coincide with the El Niño, approximately 9% of the dry surface is used by the local inhabitants as cropland, which generates a social problem during the extremely rainy years that coincide with the La Niña when the lake area increases and floods the cultivated land. In the 2001-2002 El Niño, the surface of Tecocomulco Lake decreased by 37% and the depth was 0.75-1 m. This may be associated with a higher temperature, and in consequence a high evaporation, a situation that requires corroboration through future studies.