Uso de Isotopos Estables para el Estudio de las Fuentes de Agua Superficiales en el Ecuador y sus Implicaciones para la Gestión de los Recursos Hídricos

Abstract

This study is focused on an investigation of rainfall and runoff processes in the Ecuadorian Andean Mountains with emphasis on implications to the management of hydraulic resources using of δD and δ18O values. The following question have guided this project: (1) How do the δD and δ18O values vary in runoff-rainfall processes in two adjacent watersheds that have different rainfall patterns? By answering this question, a broader question of how can hydrogen and oxygen isotope compositions be used to improve understanding of runoff sources in mountain streams and their contribution to hydraulic resource projects? First, I analyzed the temporal and spatial variation of isotope composition of rainfall data in Ecuador. I compared the previous data with surface water in streams and glaciers during two different seasons in December 2016 and April 2017. The results of this analysis exposed that rainfall isotope values are more affected by altitude and seasonal factors than amount effect factors. Although in hydrologic studies, surface water is difficult to understand, in this case, the results in runoff during both months expose the same variation of the rainfall values.  This dependency exposes the high potential that stables isotopes have to represent and understand the sources of surface water in Ecuador.