Evaluation of overland flow modelling hypotheses with a multi-objective calibration using discharge and sediment data

Area of Science:

• Hydrology
• Environmental Science
• Water Resource Management

Background:

• Conceptual hydrological models often aggregate catchment-scale processes, limiting detailed understanding of water pathways and travel times.
• Discharge observations alone may not sufficiently differentiate hydrological processes like overland flow.

Purpose of the Study:

• To evaluate if incorporating sediment data can improve the distinction between overland flow and total discharge in hydrological models.
• To assess the impact of multi-objective calibration on discharge and suspended sediment simulation performance.

Main Methods:

• Applied multi-objective calibration to the World-Wide Hydrological Predictions for the Environment (HYPE) model.
• Utilized both discharge and suspended sediment concentration data for calibration across 111 US catchments.
• Tested new overland flow hypotheses to reduce model complexity.

Main Results:

• Multi-objective calibration significantly improved suspended sediment simulation performance.
• Discharge simulation performance remained largely unaffected by the multi-objective calibration.
• Proposed overland flow hypotheses yielded comparable discharge results with fewer parameters, reducing equifinality.

Conclusions:

• Integrating sediment data enhances hydrological model process understanding, particularly for water quality applications.
• Multi-objective calibration is effective for improving sediment transport modeling without compromising discharge accuracy.
• Reduced model complexity through refined overland flow hypotheses is beneficial for data-poor environments.