Overview
One of the negative impacts of polluting activities on aquatic ecosystems is the loss of a river’s natural self-purification ability. This research evaluated the Sinú River’s capacity to assimilate wastewater discharges using a water quality model-based methodology.
Model Setup
Monitoring of several water quality parameters was carried out in the river across different seasons. The Environmental Fluid Dynamics Code model was used to simulate different scenarios, with calibration tested using the Root Mean Square Error. After calibration, scenarios involving increases and decreases in discharge concentrations, discharge flows, and river flows were simulated, and the results were compared to water quality reference limits.
Key Findings
The model accurately represented the real conditions of the studied river section for all evaluated parameters. Assimilative capacity was affected most by the scenario in which river flow was decreased by 50% while flows and discharge concentrations were increased fivefold — causing ammonia nitrogen, chemical oxygen demand, phosphates, and total nitrogen to exceed reference limits, with maximum concentrations of 2.7, 30.9, 0.98, and 6.3 mg/L respectively. Higher concentrations were generally found in the dry season, when lower velocities and river flows reduce pollutant mixing and dilution. The spatiotemporal simulations make the methodology an essential tool for water management and the development of water quality objectives by stakeholders and environmental authorities.