Relocation of Dredged Material from Marano and Grado Lagoon: An Example of Sustainable Management

Abstract

The high degree of dynamism of coastal and lagoon morphodynamic processes often implies the need for dredging operations to maintain the navigability of the main waterways towards harbours or sites which have important tourist or economical value. In particular, within sheltered and shallow lagoons this phenomenon is continuous and involves large volumes of material that requires to be properly managed. The dredged materials can provide sediments for environmental enhancement and they can be used, as an example, to create or improve habitats, mudflats and salt marshes. Numerical model can be a valuable tool to investigate the morphological evolution of the disposals, especially in the medium term, with the aim of verifying the sediment stability and the bed level changes. The present paper shows an example of sustainable management of cohesive materials dredged from two channels of the Marano and Grado lagoon. The non-linear interactions between tidal currents and locally generated wind waves are reproduced by means of a coupled spectral-hydrodynamic model associated with a transport equation to compute sediment load concentration. The comparison of the results confirms the validity of the adopted procedure.