Pilbala et al. (2026) Dune Evanescence at Flood Stage in Lowland Sand‐Bed Rivers: A 2D Modeling Approach With Dynamic Resistance

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Water Resources Research
• Year: 2026
• Date: 2026-09-01
• Authors: Ashkan Pilbala, Federica Baldasso, Davide Tognin, Tommaso Lazzarin, Daniele Pietro Viero
• DOI: 10.1029/2026wr044363

Research Groups

• Department of Civil Engineering, University of Padua (Italy)
• National Research Council (CNR) - Institute for Coastal Marine Environment (ISMAR), Italy

Short Summary

This study enhances a 2D hydrodynamic model to account for bedform evolution and applies it to the Po River in Italy to analyze conveyance shifts caused by dune evanescence during floods, improving flood prediction and flow capacity assessment.

Objective

• Investigate the effects of subaqueous dune evanescence on flow resistance and flood propagation in lowland sand-bed rivers with very low Froude numbers.

Study Configuration

• Spatial Scale: 200 km reach of the Po River (Italy)
• Temporal Scale: Flood events

Methodology and Data

• Models used: Enhanced 2D depth-averaged fixed-bed hydrodynamic model
• Data sources: Field observations, satellite imagery, and reanalysis datasets

Main Results

• The study demonstrates a marked resistance reduction at flood stage due to dune wash-out into upper-stage plane bed, occurring at very low Froude numbers (∼0.2) and initiating at approximately 60% of the maximum flow capacity.
• Enhanced with the Van Rijn roughness predictor, the model enables accurate water level predictions under all flow conditions.

Contributions

• This study provides new insights into the effects of subaqueous dune evanescence on flow resistance and flood propagation in lowland sand-bed rivers, improving our understanding of flow-bedform interactions.
• The enhanced hydrodynamic model can be applied to other lowland alluvial rivers to improve flood prediction and flow capacity assessment.

Funding

• This research was funded by the Italian Ministry of Education, University and Research (MIUR) through the project "Hydro-Morphodynamic Modeling for Flood Risk Assessment" (PRIN 2017).

Citation

@article{Pilbala2026Dune,
  author = {Pilbala, Ashkan and Baldasso, Federica and Tognin, Davide and Lazzarin, Tommaso and Viero, Daniele Pietro},
  title = {Dune Evanescence at Flood Stage in Lowland Sand‐Bed Rivers: A 2D Modeling Approach With Dynamic Resistance},
  journal = {Water Resources Research},
  year = {2026},
  doi = {10.1029/2026wr044363},
  url = {https://doi.org/10.1029/2026wr044363}
}