Tracing water paths through small catchments under a tropical montane rain forest in south Ecuador by an oxygen isotope approach

Our findings suggest that water flow paths through the ecosystem are dominated by vertical directions through the soil profile to the stream channels during normal wet conditions, interrupted by short-term flow direction changes to lateral pathways mainly in the organic layers during rainstorm events. Results from an isotope two-component hydrograph separation for the three microcatchments showed that new rain water ('event water') contributed 81, 44, and 78% to the total stormflow runoff during peak discharge of a studied rainstorm event, respectively.