Runoff generation from a combined glacier and páramo catchment within the Antisana Reserve in Ecuador

Abstract

Runoff processes in glacier and páramo catchments in the Andean region are of interest as they are vitally important to serve the water needs of surrounding communities. Particularly in Northern Ecuador, the runoff processes are less well-known due to the high variability of precipitation, young volcanic ash soil properties, soil moisture dynamics and other local factors. Previous studies have shown that the melting of glaciers contributes to runoff generation and that the páramo ecosystem plays an important role in regulating runoff during periods of low precipitation. Data collection and experimental investigations were carried out in a catchment of 15.2 km² and altitude ranging between 4000 and 5700 m above sea level. Environmental tracers and hydrochemical catchment characterization were used for identifying runoff sources and their respective contributions during dry and wet conditions. Dry conditions are defined as periods where precipitation was absent for at least three consecutive days and wet conditions imply rainfall events. This study highlights the importance of the páramo on contributing to total runoff during baseflow (70% of total runoff) and the capacity of the páramo to dissipate the stream energy and buffer the peak flow during rainfall conditions. Electrical conductivity together with stable isotopes were identified as conservative tracers that characterize the end-member concentrations.

Keywords:

• Environmental tracers
• runoff generation
• water chemistry
• páramos
• tropical grasslands

Acknowledgements

Other institutions that also cooperated in the provision of key information and data are EPMAPS (Empresa Pública Metropolitana de Agua Potable y Saneamiento de Quito), EPN (Escuela Politécnica Nacional), INAMHI (Instituto Nacional de Meteorología e Hidrología), INIGEMM (Instituto Nacional de Investigación Geológico Minero Metalúrgico). The authors express their sincere gratitude to Fred Kruis, Ferdi Battes and Berend Lolkema for their assistance in the laboratory analysis. Thanks also to Aline Saraiva Okello, Lydia Cumiskey; and to Gareth Bird for proof-reading the manuscript. The opinions expressed in this paper are those of the author(s) and do not necessarily reflect views of any of the Institutions named above.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support came from SENESCYT (Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovación) and from the Dutch Ministry of Foreign Affairs (DUPC program at UNESCO-IHE).