Sanda et al. (2025) Assessing the adequacy of three-component hydrograph separation for runoff partitioning in a small forest catchment

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-20
• Authors: Martin Sanda, Martin Zdvorak, Tomas Vogel, Jaromir Dusek
• DOI: 10.1016/j.jhydrol.2025.134648

Research Groups

• Czech Technical University in Prague, Faculty of Civil Engineering, Prague, Czech Republic

Short Summary

This study assessed the adequacy of three-component hydrograph separation for runoff partitioning in a small forest catchment, focusing on the magnitude and persistence of tracer-based uncertainties throughout rainfall-runoff events. It revealed that significant and sometimes physically implausible uncertainty can persist when end-member tracer signatures are similar, emphasizing the need for comprehensive uncertainty evaluation across full event hydrographs.

Objective

• To examine the magnitude and persistence of uncertainties in tracer-based water fractions throughout entire rainfall-runoff events when using three-component hydrograph separation in a small forest catchment.

Study Configuration

• Spatial Scale: A small forest headwater catchment.
• Temporal Scale: Several rainfall-runoff events.

Methodology and Data

• Models used: Three-component hydrograph separation based on a mass balance approach.
• Data sources: Streamflow observations, stable oxygen isotope in water (¹⁸O) and silica concentrations as natural environmental tracers, laboratory tracer concentration measurements, and spatial variability in soil water and groundwater tracer concentrations.

Main Results

• Across five of seven events, pre-event soil water constituted the largest mixing fraction during peak flow.
• Pre-event groundwater and event water contributions varied, ranging from 22% to 65% and 9% to 43% of total streamflow volume, respectively.
• Mixing fractions demonstrated high sensitivity to changes in the pre-event isotopic composition of soil water and groundwater.
• Uncertainty intervals often extended beyond physically possible limits, even when only considering laboratory measurement errors.
• Notable and sometimes physically implausible uncertainty can persist throughout events when tracer signatures of end-members and streamflow are similar.

Contributions

• This study highlights the critical need for evaluating uncertainty across full event hydrographs, rather than only at peak or average flow conditions, especially when end-member tracer concentrations are similar.
• It provides a detailed assessment of the persistence and magnitude of uncertainties in three-component hydrograph separation, an aspect less explored in existing literature.

Funding

• Not specified in the provided text.

Citation

@article{Sanda2025Assessing,
  author = {Sanda, Martin and Zdvorak, Martin and Vogel, Tomas and Dusek, Jaromir},
  title = {Assessing the adequacy of three-component hydrograph separation for runoff partitioning in a small forest catchment},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134648},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134648}
}