Assessment of Dredging/Dumping Scenarios for Figueira da Foz Coastal Region (W Portugal)

• Published in: Journal of coastal research Vol. SI; no. 85; pp. 1266 - 1270
• Main Authors: Fernández-Fernández, Sandra, Coelho, Carlos, Bernardes, Cristina, Silva, Paulo A, Ferreira, Caroline, Ribeiro, Américo S, Abreu, Tiago, Romão, Soraia, Baptista, Paulo, Fontán-Bouzas, Ángela, Dias, João M
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Allen Press Inc 01.01.2018
• Subjects: Bottom trawling; Coastal zone; Coastal zone management; Coasts; Computer simulation; Current velocity; Decision making; Dredging; Dumping; Estuaries; Estuarine dynamics; Flow velocity; Harbors; Hydrodynamics; Inlets (waterways); Mathematical models; Modelling; Morphology; Navigation; Neap tides; Ocean dumping; Orbital velocity; Parameters; Sand bars; Sediment transport; Shoaling; Significant wave height; Significant waves; Solutions; Tidal currents; Velocity; Wave climate; Wave direction; Wave height; United States > US; Atlantic Ocean; Portugal
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/S185-254.1

Figueira da Foz coastal region (W Portugal), that comprises sandy beaches and the Mondego estuary-inlet, is exposed to the high energetic wave climate of the North Atlantic Ocean, which induces important local morphological changes. These changes entail shoaling problems as the formation of a submerse sandbar at the inlet which can block navigation towards local harbor. Therefore, coastal dredging is a non-structural temporal solution for this problem. Nevertheless, dredging activities have an impact on local hydrodynamic processes that should be known beforehand. The aim of this study is to clarify this issue using modeling tools dedicated to help stakeholders in decision making process. For that purpose, Delft3D-WAVE module propagates the most representative regional wave conditions under four dredging scenarios including the respective dump areas. Additionally, Delft3D-FLOW module simulates tidal flows along spring and neap tides. The hydrodynamic parameters, significant wave height, orbital velocity, wave-induced currents, tidal current velocity and total sediment transport are analyzed in comparison with numerical solutions obtained in reference scenario (no dredging and no dumping). The results highlight changes in these hydrodynamic parameters in dredging and dumping areas as well as in surrounded areas. Different scenarios draw a similar change pattern for different parameters, namely a reduction of flow velocity intensity within dredged areas and their increase in adjacent areas. Furthermore, hydrodynamic alterations intensify in response to the increase in significant wave height and wave direction considered. These findings are the basis for understanding the influence of dredging and dumping operations on the hydrodynamic of this coast.