Improvement in the Sediment Management of a Lagoon Harbor: The Case of Marano Lagunare, Italy

Abstract

Port silting is a common and natural process which often causes serious inconveniences for safe navigation and requires expensive dredging operations to keep the port operative. Sediment deposition is closely related to the exchange water between the basin and the surrounding environment; one way to limit deposits is by reducing the flow entering the port. However, this may be in contrast with the need for adequate sediment quality, which in turn is closely related to an appropriate water current. This seems to be particularly important in lagoon environments, where sediments are often polluted, making its disposal more complicated and costly. The present paper investigates the situation of the port of Marano Lagunare (Italy) by means of a bidimensional morphological-hydrodynamic and spectral coupled model. To reduce the sediment input into the port, the closure of a secondary port entrance is usually suggested. However, this work demonstrates that a complete dredging of the secondary port inlet allows for an increase in water circulation or efficiency renewal, which ensures a better oxygenation at the bottom of the canals.

Mediterranean Coastal Lagoons Review: Sites to Visit before Disappearance

“…On the other hand, the effect that navigation waves have also affects shoreline erosion in places with high traffic such as Venice [62]. Navigation inside the lagoons, not only for fishing, has also been a historical activity when there is an opening to the sea; this makes inland ports where the stay of ships is ensured, and therefore also affects water quality; in the case of Marano, for example, it has required dredging the bottom to provide navigation channels [63]. In other lagoons it has required opening the channel of communication with the sea to maintain a significant and deep opening, as in lagoons in southern France, in Marchica [64] and Bizerte [65].…”

Geochemical Characterization of Sediments from the Bibione Coastal Area (Northeast Italy): Details on Bulk Composition and Particle Size Distribution

“…The dredged sediments must have high chemical and ecotoxicological quality to be reused in other contexts. If the sediments are of poor quality, they must be treated or disposed of in landfills, resulting in significant increases in management costs for port activities [7].…”

“…Occasionally, due to their geomorphological features, lagoon areas may also host small port activities. As semi-enclosed basins, lagoons should be potentially more exposed to pollution phenomena than the coastal areas, with repercussions both from environmental and economic points of view [7]. Furthermore, considering lagoons as low energy environments, where silting phenomena can make navigation impossible, dredging works are most of the time inevitable to restore hydraulic functionality.…”

“…Furthermore, considering lagoons as low energy environments, where silting phenomena can make navigation impossible, dredging works are most of the time inevitable to restore hydraulic functionality. Therefore, if the sediments of these areas are polluted, they cannot be reused as they are and must be adequately disposed of (or subjected to reclaiming operations for possible reuse), with very high management costs [7]. The quality of the sediments of a lagoon depends both on anthropic and natural factors, such as in the Nador lagoon area (Northeast Morocco), where human activities have contributed significantly to the heavy pollution of the sediments that characterize it [8]; other lagoons have similar issues [9][10][11].…”

Development of a Complex Vulnerability Index for Fishing Shelters—The Case of Cyprus

“…Sediment transport, especially when sediment motion is mainly due to suspension, can hinder the approach of fishing boats due to the potential accumulation of sediment in the channel entrance, thus reducing the depth in the fishing shelter basin [33]. Fine sand, silt, and clay sediments, present in mud flats deltas and sandy beaches, are more easily set in suspension due to wave stirring and are associated with increased vulnerability.…”