BEACH PROCESSES AND SHORE PROTECTION ALONG THE NORTHERN COLOMBIA COAST

The shoreline of northern Colombia is located in the tropical zone along the south coast of Caribbean Sea. Its coastal processes are strongly influenced by the northeast trade wind, which results in the dominating northeasterly approaching wave occurring over 95% of the time. This drives a persistent southwestward longshore sand transport. The state of the beach along the generally northeast-southwest trending northern Colombia coast is strongly influenced by this constant unidirectional longshore sediment transport. At locations where this westward longshore sand transport is interrupted, naturally or anthropogenically, beach accretion occurs along the updrift shoreline coupled with erosion at the downdrift side. Natural interruption of longshore transport can be caused by tidal inlets, protruding headland, shoreline orientation change, and nearshore bathymetry variations. Anthropogenic interruption of the longshore transport along the northern Colombia coast is mainly caused by the construction of groins, as well as harbors at some locations. Numerous groins were constructed due to their local success in creating beach accretion at the drift side. However, severe beach erosion occurs along the downdrift shoreline. Shoreline protection along the northern Colombia coast, and coasts in the tropical area in general, should carefully consider the persistent unidirectional longshore sand transport and should not be misguided by the local updrift accumulation as being a successful project.