Overview
Deltas are strategic systems of high ecological and economic importance, providing environmental resources and fertile alluvial soils. Among the hydrodynamic processes occurring in deltas is saline intrusion. This study implemented a three-dimensional numerical modeling system using the EFDC+ Explorer Modeling System to analyze the characteristics of saline intrusion in the Sinú River delta, Colombia.
Model Setup
The model was configured with field data from two measurement campaigns in February and November 2021 — dry and wet seasons respectively — along with secondary information. Several climatic conditions were simulated to cover a wide range of variability in the main forcing factors, river discharge and tides: without the influence of the El Niño Southern Oscillation (ENSO), under critically low flow discharge conditions, and with sea level rise forecasts. The model was calibrated using in-situ water velocity data and salinity profiles, achieving Index of Agreement values between 0.67 and 0.99 for salinity and above 0.9 for water velocity.
Key Findings
The simulations demonstrated that river discharges above 319 m³/s — typical values registered annually between May and November — were sufficient to prevent salt wedge intrusion. Scenarios under critical low discharge conditions and sea level rise projections showed a maximum salt wedge intrusion reach of 7.40 km. The model proved efficient at evaluating the saline intrusion process, and the study shows that simulating physical processes such as salinity stratification provides useful information on how these estuarine systems respond to environmental stressors associated with climate variability — important because salinity gradients influence phytoplankton distribution and primary productivity in deltas.