Participation in the Spanish Coastal and Port Engineering Conference (Huelva, 2026)

Pedro Otiñar participated in the Spanish Coastal and Port Engineering Conference, held in Huelva on 13–14 May 2026, presenting the study “Retrospective analysis of salinity in the Guadalquivir Estuary since the implementation of the regulation system at Alcalá del Río”, authored by Manuel Cobos, Pedro Otiñar, Marcus Silva, Asunción Baquerizo, and Manuel Díez‑Minguito.

The contribution examines how nearly a century of river regulation, dredging activities, and morphological alterations has reshaped the hydrodynamics and salinity structure of the Guadalquivir Estuary—one of the most heavily modified estuaries in Europe. Using a long‑term numerical reconstruction (1931–2025) based on the BARRIER 1D model, the study integrates historical discharge records, reconstructed tidal levels, and multi‑decadal bathymetric datasets to quantify the evolution of tidal propagation and salt intrusion.

Results reveal a progressive upstream shift of key isohalines (2, 5, and 10 PSU) since the 1970s, with displacements approaching 20 km under low‑flow conditions. The analysis highlights the strong influence of regulated freshwater releases, particularly the timing, magnitude, and intermittency of discharge events, on salinity dynamics and residence times.

This work provides one of the first multi‑decadal, model‑supported assessments of salinity evolution in the Guadalquivir Estuary, offering valuable insights for water‑resource management, ecological conservation, and future adaptation strategies.

Participation in the Ocean Sciences Meeting: Salt Intrusion Prediction under Climate‑Scale Variability

Manuel Díez‑Minguito participated in the Ocean Sciences Meeting 2026 in Glasgow, presenting recent advances on the prediction of salt intrusion in estuaries under climate‑scale variability. The contribution focused on a novel statistical–dynamical framework to estimate the salinity intrusion reference point X2 using equiprobable, non‑stationary freshwater discharge scenarios.

The study applies this methodology to the Guadalquivir Estuary (Spain), a well‑mixed and strongly regulated system where freshwater releases play a key role in controlling salinity. Using an idealized cross‑sectionally averaged model, the team conducted a 100‑year hindcast simulation, revealing a bimodal probability distribution of X2: one mode associated with typical low‑flow conditions, and a second mode linked to high‑flow events that temporarily shift X2 seaward.

Results show that dam operations, particularly impulsive releases, exert a strong influence on the distribution of X2. A clear non‑stationary trend emerges over the century‑long simulation, with X2 gradually shifting upstream as freshwater availability declines.

To explore future conditions, the team generated synthetic river‑flow time series using a combination of non‑stationary probability distribution fitting and vector autoregressive modelling, producing equiprobable discharge scenarios consistent with projected climate trends. These series enabled climate‑scale projections of X2 up to the year 2100, capturing long‑term tendencies and uncertainty in freshwater inputs.

This work provides a robust framework for anticipating salinity intrusion under changing hydrological regimes

Development of the Guadalquivir Data Viewer

As part of the BARRIER project’s digital ecosystem, we have developed an interactive web-based data viewer designed to explore, compare, and communicate the key datasets underpinning the hydrodynamic and biogeochemical analysis of the Guadalquivir estuary. The tool provides a lightweight and accessible interface that brings together the most relevant observational and model-derived information currently available in the project.

The viewer integrates the updated and curated datasets that correspond to the present stage of development, including:

  • Bathymetry and topography from field campaigns
  • Hydrodynamic and salinity observations from field campaigns
  • River discharge and water-level data from national monitoring networks
  • Meteo-oceanographic reanalyses and projections from CMIP5 and Copernicus (E‑HYPEcatch)

All sources have been harmonized, validated, and updated to ensure consistency across spatial and temporal scales. This process includes gap‑filling using advanced data‑driven techniques, currently being formalized in Navarro et al. (2026, in preparation).

The platform allows users to visualize time series, spatial fields, salinity patterns, water levels, flows, and sediment‑related diagnostics, with synchronized temporal navigation and the ability to compare scenarios or datasets side by side. Additional tools enable point inspection, layer control, and the export of visual outputs for technical reporting.

The viewer is conceived as a modular and extensible component of the project. Its architecture supports the progressive incorporation of new datasets and diagnostics as the project advances, ensuring transparency, reproducibility, and reusability for other research groups and stakeholders.

Ultimately, this tool strengthens the project’s commitment to open science and knowledge transfer, offering researchers, managers, and the public a clear and intuitive way to explore the dynamics of the Guadalquivir estuary.