Browsing by Author "Correa Barahona, Alicia Beatriz"

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Do mixing models with different input requirement yield similar streamflow source contributions? Case study: a tropical montane catchment
(2021) Timbe Castro, Edison Patricio; Crespo Sánchez, Patricio Javier; Mora Abril, Enmita Lucía; Ramón Flores, Jorge David; Correa Barahona, Alicia Beatriz; Mosquera Rojas, Giovanny Mauricio
Hydrogeochemical based mixing models have been successfully used to investigate the composition and source identification of streamflow. The applicability of these models is limited due to the high costs associated with data collection and the hydrogeochemical analysis of water samples. Fortunately, a variety of mixing models exist, requiting different amount of data as input, and in data scarce regions it is likely that preference will be given to models with the lowest requirement of input data. An unanswered question is if models with high or low input requirement are equally accurate. To this end, the performance of two mixing models with different input requirement, the mixing model analysis (MMA) and the end-member mixing analysis (EMMA), were verified on a tropical montane headwater catchment (21.7 km2) in the Ecuadorian Andes. Nineteen hydrogeochemical tracers were measured on water samples collected weekly during 3 years in streamflow and eight potential water sources or end-members (precipitation, lake water, soil water from different horizons and springs). Results based on 6 conservative tracers, revealed that EMMA (using all tracers) and MMA (using pair-combinations out of the 6 conservative ones), identified the same end-members: rainfall, soil water and spring water., as well as, similar contribution fractions to streamflow from rainfall 21.9% and 21.4%, soil water 52.7% and 52.3%, and spring water 26.1% and 28.7%, respectively. Our findings show that a hydrogeochemical mixing model requiring a few tracers can provide similar outcomes than models demanding more tracers as input data. This underlines the value of a preliminary detailed hydrogeochemical characterization as basis to derive the most cost-efficient monitoring strategy.
Spatially distributed hydro-chemical data with temporally high-resolution is needed to adequately assess the hydrological functioning of headwater catchments
(2019) Correa Barahona, Alicia Beatriz; Breuer, Lutz; Crespo Sánchez, Patricio Javier; Célleri Alvear, Rolando Enrique; Feyen, Jan; Birkel, Christian; Silva Alemán, Camila Fernanda; Windhorst, David
Abstract We demonstrated the great value of spatially distributed and temporally high-resolution hydro-chemical data to enhance knowledge about the intra-catchment variability of flow processes and the runoff composition of individual storms in a tropical alpine (Paramo) ecosystem. In this study, water sources (rainfall, spring water, and water from soil layers of Histosols and Andosols) and nested streams were sampled bi-weekly (2013–2014), including three storm high-resolution events (5–240 min). Water samples were analyzed for 14 tracers including electrical conductivity (EC) and rare earth trace elements and used as input to perform End-Member Mixing Analysis (EMMA). End-members identified for the outlet could explain the hydrological behavior of four out of the five tributaries, indicating similar hydro-geochemical processes and geomorphic features within the catchments. The runoff source contributions of the individual sub-catchments varied among (e.g. Andosols ~40% in tributaries and ~25% at the outlet) and within storm events (e.g. Histosols 15% higher in small peak discharge event), indicating a time-variable composition of streamflows. The latter was also reflected by the interaction of different sources and the chronology of flow paths in EMMA-space, evidencing a faster connectivity with hillslopes in the upper sub-catchments compared to the lower sub-catchments. We found counter-clockwise hysteresis patterns of storms in the lower catchments and clockwise hysteresis loops in the upper catchments. The latter bi-directionality can be related to lower slopes, wider riparian areas and the higher proportion of Histosols in the lower catchments compared to the upper sites.
Using the fuzzy cognitive map approach to promote nature-based solutions as a strategy to improve water quality in Ecuadorian communities
(European Geosciences Union, 2022) Fonseca, Kalina
An adequate strategy for water quality improvement in developing countries must consider the economic scarcity of water, the external factors that affect its quality, and the participation of multisectoral stakeholders in water management decisions. In addition, stronger links to nature can be established through methods inspired from nature to clean the water, such as artificial floating islands (AFI). Restoration of aquatic ecosystems with AFIs occurs as water passes beneath the floating mat and the roots of macrophytes take up metals and nutrients. In this context, we utilized Fuzzy Cognitive Maps (FCMs) to identify the principal concepts that affect water quality from different perspectives: political, economic, social, technological, environmental, and legal (PESTEL). We also theoretically explore the use of AFIs combined with different policies, to find the strategy that best adapts the local water situation.