Estimación de la fracción de agua de evento y pre evento que aportan al caudal, mediante el uso de isótopos estables, en la Cuenca del río Zhurucay

Abstract

In recent years the hydrological information related to paramo has become very important for the ecosystem services provided in the social, economic and environmental fields. Researches conducted in this topic are still necessary to clarify and understand its operation and hydrological dynamics. To estimate the fraction of event and pre-event water sources contributing runoff to flow during rainfall events using mixture models was analyzed isotopic data (oxygen 18) of precipitation and flow of the river basin Zhurucay for the period February - April 2014. Analysis of the results shows that the pre-event water is predominant, reaching up to 98% depending on the antecedent moisture and rainfall intensity. A high correlation of the percentage of pre-event water with the Histosolsand Andosolssoils is observed(r2 = 0.7), showing the importance of the characteristics and physicochemical properties of these soils in runoff generation. The results subject to an uncertainty analysis revealed a variation range between 4 and 31% and they can be considered reliable. Although cases where 100% greater uncertainty were also given, being the main contributor the eventwater component; so the results for these should be interpreted with caution.