1. A simple mixing model using electrical conductivity yields robust hydrograph separation in a tropical montane catchment.
- Author
-
Lazo, Patricio X., Mosquera, Giovanny M., Cárdenas, Irene, Segura, Catalina, and Crespo, Patricio
- Subjects
- *
ELECTRIC conductivity , *MATHEMATICAL models , *COMPUTATIONAL complexity , *STREAMFLOW , *CONCEPTUAL models - Abstract
• Pre-event water concentration has a major role on hydrograph separation. • Event water concentration has little influence on hydrograph separation results. • Pre-event water concentration should be determined for each rainfall-runoff event. • Simple and complex hydrograph separation models give similar results. • Electrical conductivity yields similar results than Oxygen-18. Hydrograph separation assessment is crucial to understand stormflow generation at catchments worldwide. Tracer-based methods provide robust estimations of event (or new) and pre-event (or old) water fractions as they account for external and internal catchment hydrological behavior. While models of different mathematical and computational complexity are often used in tracer-based hydrograph separation studies, direct comparisons between those models are limited. Here, we compare hydrograph separation results yielded by the simplest Two-Component Mixing Model (TCMM) and a Tracer-based Streamflow Partitioning ANalysis model (TraSPAN) assumed to provide robust results as it combines conceptual rainfall-runoff modelling with tracers' mass balance. We carried out the analysis using high temporal frequency (sub-daily to sub-hourly) data of two tracers, Oxygen-18 and Electrical Conductivity (EC), monitored during 37 rainfall-runoff events with different hydrometeorological conditions in a high-Andean páramo catchment located at the Zhurucay Ecohydrological Observatory in southern Ecuador. Both approaches yield similar estimations of event and pre-event water fractions regardless of the tracer used as long as appropriate concentrations of event (C e) and pre-event (C p) water for the TCMM are determined. Although the estimate of C e has little influence with one rainfall sample collected during the event being sufficient to obtain reliable results, results hinge heavily on the estimate of C p. We found that the TCMM yields similar results than TraSPAN when C p is represented by the stream water concentration corresponding to a sample collected prior to the beginning of each of the events. We conclude that the combination of a simple framework (TCMM) with sub-hourly EC measurements provides reliable hydrograph separation results when representative C p samples are used. These findings will allow to lower the logistical and economical resources needed to adequately assess hydrograph separation and to carry out quasi-continuous assessments of flow partitioning with high accuracy in high-Andean páramo catchments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF