Categoría: Transferencia

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.

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