Environmental assessment of pre-dredging sediments and proposals for their subsequent management in the port of Mar del Plata, Buenos Aires, Argentina

Resumo

Nowadays, the discharge of dredged sediments into the sea is one of the most important problems in the management of coastal areas; therefore, the characterization and handling of the materials to be dredged is of utmost importance. Since its creation, the Port of Mar del Plata, Buenos Aires, Argentina, has presented a structural difficulty that affects its operation: the interruption of the strong littoral drift by its breakwaters generates an important sand sedimentation blocking the access channel. This hampers the entry and maneuverability of large ships, while promoting sediment imbalances on a regional scale, causing coastal erosion on many beaches. At present, the administrative authorities of the port are proposing a new dredging work in order to restore adequate navigation depths. On this basis, the aim of this work was to characterize the current sediment of the Port of Mar del Plata and compare it with previous results from 1996. Grain size, water content and organic matter were monitored at 12 stations. The results indicate that the external sector receives a larger share of sand than in 1996. Muds become preferentially deposited at the inner docks. Organic matter, with increases compared to the previous study, accumulates in the inner docks with lower water renewal.  Based on these results, this work proposes certain management alternatives for dredged sediments. Among them, beach nourishment stands out, with the aim of mitigating the effects caused by the port on the regional sediment dynamics.