Pereira et al. (2025) Linking ROMS with watershed models for simulating hydrodynamics and thermohaline dynamics in a coastal lagoon affected by extreme weather events

Identification

• Journal: Ocean Modelling
• Year: 2025
• Date: 2025-12-12
• Authors: Francisco Pereira, Francisco López-Castejón, Félix Francés, Andrés Alcolea, Joaquín Jiménez‐Martínez, João Miguel Días, Javier Gilabert
• DOI: 10.1016/j.ocemod.2025.102673

Research Groups

• Department of Chemical and Environmental Engineering, Universidad Politécnica de Cartagena, Spain.
• Centre for Environmental and Marine Studies (CESAM), Physics Department, Universidade de Aveiro, Portugal.
• Department of Applied Physics and Naval Architecture, Universidad Politécnica de Cartagena, Spain.
• Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Spain.
• HydroGeoModels AG, Switzerland.
• Eawag, Dübendorf, Switzerland.
• Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Switzerland.

Short Summary

The study develops and validates a linked numerical modeling system (ROMS-TETIS-SUTRA) to simulate the hydrodynamics and thermohaline structure of the Mar Menor lagoon. It demonstrates that extreme flash floods, such as the September 2019 event, trigger long-lasting vertical stratification and significantly reduce the lagoon's water renewal time.

Objective

• To develop and validate a hydrodynamic model linked to watershed and groundwater models capable of accurately reproducing the Mar Menor’s dynamics under both normal conditions and extreme weather events (flash floods).

Study Configuration

• Spatial Scale: The Mar Menor coastal lagoon (136.1 km²) and its adjacent Mediterranean nearshore. The numerical grid resolution ranges from 15 m in narrow inlets to 50 m in the central lagoon.
• Temporal Scale: Validation conducted over the years 2021 and 2022, with a specific high-resolution analysis of the September 2019 Cut-off Low (CoL) flash flood event and its one-month recovery period.

Methodology and Data

• Models used:
  • ROMS (Regional Ocean Modelling System): 3D hydrodynamic model with 10 vertical terrain-following layers.
  • TETIS: Spatially-distributed eco-hydrological model for surface runoff.
  • SUTRA: Finite-element simulator for saturated-unsaturated, variable-density groundwater flow.
  • HARMONIE-AROME: Atmospheric forcing model (AEMET).
• Data sources:
  • In-situ observations: 7 tide gauges for sea level, 5 ADCPs for currents, and multiple CTD profiles for salinity and temperature.
  • Satellite/Reanalysis: Sentinel-2 imagery, IEO bathymetry, and Copernicus Marine Service (IBI-Ocean Physics Reanalysis) for oceanic boundaries.

Main Results

• Model Accuracy: High performance in sea level reproduction (RMSE 0.9–1.1 cm; Skill > 0.99) and current velocities (Skill > 0.90).
• Stratification Dynamics: The September 2019 CoL event induced extreme vertical salinity gradients (up to 30 units) that persisted for over a month.
• Physical Mechanisms: Stratification was maintained because the Richardson number remained significantly above the critical value of 0.25, indicating that buoyancy forces from freshwater input overwhelmed the shear instability generated by wind and bi-layer currents.
• Water Renewal: The flash flood event caused a nearly 20% reduction in the lagoon's Water Renewal Time (WRT), shortening it by 52 days (from 269 to 217 days).

Contributions

• Provides the first comprehensive validation of a linked hydrodynamic-hydrological-groundwater model for the Mar Menor using a robust multi-parameter dataset.
• Quantifies the impact of extreme "DANA" (CoL) events on the vertical structure and flushing efficiency of a microtidal lagoon.
• Establishes a validated modeling framework suitable for future coupling with biogeochemical and sediment transport modules to support ecosystem management.

Funding

• Consejería de Medio Ambiente, Universidades, Investigación y Mar Menor of the Comunidad Autónoma de Murcia.
• THINKINAZUL program (MICIU) with EU NextGenerationEU (PRTR-C17.I1) funding.
• Fundación Séneca (Comunidad Autónoma Región de Murcia).
• FCT – Fundação para a Ciência e a Tecnologia I. P. (CESAM: UID/50017/2025 and LA/P/0094/2020).

Citation

@article{Pereira2025Linking,
  author = {Pereira, Francisco and López-Castejón, Francisco and Francés, Félix and Alcolea, Andrés and Jiménez‐Martínez, Joaquín and Días, João Miguel and Gilabert, Javier},
  title = {Linking ROMS with watershed models for simulating hydrodynamics and thermohaline dynamics in a coastal lagoon affected by extreme weather events},
  journal = {Ocean Modelling},
  year = {2025},
  doi = {10.1016/j.ocemod.2025.102673},
  url = {https://doi.org/10.1016/j.ocemod.2025.102673}
}

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