Temporal dynamics in dominant runoff sources and flow paths in the Andean Páramo

Alicia Correa*, David Windhorst, Doerthe Tetzlaff, Patricio Crespo, Rolando Célleri, Jan Feyen, Lutz Breuer

*Corresponding author for this work

Research output: Contribution to journalArticle

21 Citations (Scopus)
6 Downloads (Pure)

Abstract

The relative importance of catchment's water provenance and flow paths varies in space and time, complicating the conceptualization of the rainfall-runoff responses. We assessed the temporal dynamics in source areas, flow paths, and age by End Member Mixing Analysis (EMMA), hydrograph separation, and Inverse Transit Time Proxies (ITTPs) estimation within a headwater catchment in the Ecuadorian Andes. Twenty-two solutes, stable isotopes, pH, and electrical conductivity from a stream and 12 potential sources were analyzed. Four end-members were required to satisfactorily represent the hydrological system, i.e., rainfall, spring water, and water from the bottom layers of Histosols and Andosols. Water from Histosols in and near the riparian zone was the highest source contributor to runoff throughout the year (39% for the drier season, 45% for the wetter season), highlighting the importance of the water that is stored in the riparian zone. Spring water contributions to streamflow tripled during the drier season, as evidenced by geochemical signatures that are consistent with deeper flow paths rather than shallow interflow through Andosols. Rainfall exhibited low seasonal variation in this contribution. Hydrograph separation revealed that 94% and 84% is preevent water in the drier and wetter seasons, respectively. From low-flow to high-flow conditions, all the sources increased their contribution except spring water. The relative age of stream water decreased during wetter periods, when the contributing area of the riparian zone expands. The multimethod and multitracer approach enabled to closely study the interchanging importance of flow processes and water source dynamics from an interannual perspective.

Original languageEnglish
Pages (from-to)5998-6017
Number of pages20
JournalWater Resources Research
Volume53
Issue number7
Early online date24 Jul 2017
DOIs
Publication statusPublished - Jul 2017

Keywords

  • End Member Mixing Analysis
  • hydrochemical tracers
  • Inverse Transit Time Proxies
  • mountain tropical catchment
  • temporal water dynamics
  • water stable isotopes

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    Correa, A., Windhorst, D., Tetzlaff, D., Crespo, P., Célleri, R., Feyen, J., & Breuer, L. (2017). Temporal dynamics in dominant runoff sources and flow paths in the Andean Páramo. Water Resources Research, 53(7), 5998-6017. https://doi.org/10.1002/2016WR020187