Runoff sources and flowpath dynamics in the Andean Páramo

Abstract

As a consequence of the remote location of the Andean Páramo, knowledge on their hydrologic functioning is, despite their importance as local water towers, still limited. Toimprove our understanding, we identified hydrological informative periods, defined dominantwater sources as well as flow paths and analyzed their spatio-temporal dynamics throughout the year and during events. We therefore collected hydro-metrical (2010 - 2014) and hydrochemical (2012 - 2014) information within a tropical headwater catchment (7.53 km2) in the Ecuadorian Andes. Our results showed that rainfall-runoff events and continues data sets reveal similar information and that a single event in the wet season can provide the same insights than continuous monitoring, indicating that the hydrological processes at that time are almost stationary. Further, we identified that water from the riparian zone represented the dominant contributing source to streamflow year-round and connectivity with hillslopes was particularly important during the wet season. During rainfall-runoff events, different patterns in the upper compared to the lower catchment suggested a fast reaction of fresh water and water from the riparian zone, respectively. This study demonstrated that catchments with almost stable hydrological conditions can still be characterized by varying inter-annual source contributions, related to topography and soil types occurring in the catchment.