Short-Term Effect of Dumping Dredged Materials at the Coastal Marine Environment of El Oro Province-Ecuador

Dredging is a common practice worldwide during port expansion or infrastructure modernization. Before dredging, a common question arises about what to do with the dredged materials. If they are assumed to be waste, carefully selecting the dumping site minimizes the impact on the coastal marine environment. Numerical models can simulate the behavior of the coastal system's dynamic and predict the fate of dredged materials from various offshore disposal sites. Coastal hydrodynamic and marine sediment fields in Ecuador have not been studied extensively. Therefore, the low understanding of the marine environment grants overlapping the economic benefits of dumping at sea over the marine environment matters. This research shows that if the environmental impact assessment concluded that disposing at sea is the best option, dredged materials dumped at the coastal marine environment of El Oro province have less effect when it occurs at a deeper westward deposit site. After simulating four scenarios at Delft3D, daily disposal of more than seventeen thousand cubic meters of dredged materials for six months affects seven hydrographic variables at flood and ebb tide. These scenarios show that the accumulation of dredged materials has more effects in the short term when the dumping site is shallower and closer to the dredging site. Less impact on the Ecuadorian coastal zone can be reached when dumping activities occur if simulated scenarios with a close approximation of the effects of dredged materials are run before selecting a disposal site. We anticipate this research, beyond contributing to understanding the marine environment, is also the starting point for future studies that will support Ecuador’s policymakers to establish guidelines for managing sustainably dredged materials, ratifying environmental agreements, or proposing other options for the final disposal of dredged materials at sea.