PROJECT DESCRIPTION
BACKGROUND
Harbours and tidal inlets on coastal areas are subject to a gradual deposition of littoral materials. Without maintenance of the seabed, they become unsuitable for commercial use. Traditional management involved the mechanical withdrawal of the sediments or the construction of marine infrastructures, such as entrance banks and seawards, in order to stabilise the seabed. The use of dredging equipment is the most common solution adopted, since it ensures improved navigability. In the EU, around 200-250 million tonnes (dry weight) of material is dredged in the marine environment every year. Dredging, however, has a high environmental impact on marine flora and fauna, and contributes to the mobilisation of contaminants and pollutants. It is also costly. Innovative solutions are thus required in order to ensure sustainable seabed maintenance of port inlets.
The port of Cervia in the Italian region of Emilia-Romagna undergoes cyclical inlet silting. Relevant data on port bathymetries (under water depth), in particular from 2009 to date, is available. Past technological solutions, such as seasonal dredging and sand handling through boat propellers and the lengthening docks (completed in 2009), did not solve the problem.
The Integrated Maritime Policy seeks to provide a more coherent approach to maritime issues, promoting increased coordination among different policy areas, such as blue growth, marine data and knowledge, maritime spatial planning, integrated maritime surveillance and sea basin strategies. Seabed maintenance of a port inlet is a cross-sectoral issue, since it affects economic, technological and environmental policy. Both the Marine Strategy Framework Directive and the Maritime Spatial Planning Directive encourage the matching of economic activities with environmental needs.
OBJECTIVES
The main aim of the LIFE MARINAPLAN PLUS project was to scale up an innovative and environmentally sustainable technology for marine and coastal management. This technology would be designed in order to avoid the traditional collection of littoral materials near the entrance of harbours, through the use of submerged and static devices called ejectors, which are fed by pressurised water.
Ejectors deliver a mixture of water and sediments through a pipe to suitable areas where sediments do not represent an obstacle to navigation. As a result, no turbidity or re-suspension would be produced both near the ejectors and at discharge pipeline outlets, in compliance with the Water Framework Directive (WFD), which aims to prevent the deterioration of aquatic ecosystems including coastal water areas. Plant discharge pipeline outlets would be located in marine currents in order to enable the natural removal of the sediment. Therefore, the ejectors simply would move the sediments that are naturally transported by marine currents from a critical position to another one where sediments can be taken by the same current to somewhere where sediments do not constitute an obstruction to navigation.
In compliance with the Marine Strategy Framework Directive, LIFE MARINAPLAN PLUS also aimed to draw up a plan for the management of the seabed that guarantees that economic activities related to navigability have a negligible impact on the marine environment. The project would test a demo plant and, on the basis of test results, develop a management plan for seabed maintenance that is transferable to other small- and medium-size seaports.
RESULTS
The LIFE MARINAPLAN PLUS project successfully demonstrated an innovative and reliable technology at industrial scale for seabed maintenance and the removal of sediment, to guarantee navigability at a port inlet without the need for dredging operations. This technology prevents deposits of littoral materials near the entrance of harbours, through the installation of submerged and static devices, called “ejectors”. Using pressurised water, they suck up a mixture of water and sediment and convey it, through a piping system, to an area where it does not impair navigation.
This process also led to positive ecological responses in the marine environment, due to reductions of organic matter and the muddy fraction. Species abundance and species richness increased progressively during the monitoring surveys; in the project’s last survey reaching values found in control areas. Before the plant installation, flathead grey mullet (Mugil cephalus) was the only fish species observed at the port inlet, but by the end of the project various fish species were observed including horse mackerel (Trachurus thrachurus) and striped red mullet (Mullus surmuletus).
The project obtained the ENVISION Silver certification. The ENVISION protocol is a rating system for sustainable infrastructure, which is promoted by the Institute for Sustainable Infrastructures. It is based on 60 sustainability criteria, in five categories: (i) quality of life, (ii) leadership, (iii) resources allocation, (iv) natural world, and (v) climate and risk. This award demonstrates the project partners’ commitment to sustainability, and adds value to the technology and the innovative approach to the problem of marine sediment management.
Due to some technical and economic obstacles, however, the project’s demonstration plant was decommissioned and dismantled at the project end. Though the results were encouraging, some technological improvements were still needed, especially to contain the impact of fouling and to reduce the energy consumption during the plant operations. Project beneficiaries Trevi S.p.A and the University of Bologna are working to define improved technological measures to be applied on new demonstration plants in Italy. The replication and market potential will be very high when such technical optimisations overcome the obstacles identified during the project.
The LIFE MARINAPLAN PLUS technology attracted widespread interest, including at the political level. Thanks to the support of ICOMIA (International Council of Marine Industry Association), the ejectors technology will be included in the upcoming PIANC (Permanent International Commission for Navigation Congresses) Technical Report 130 “Anti-Sedimentation Systems for Marinas and Yacht Harbours”.
Further information on the project can be found in the project's layman report (see "Read more" section).
