MOSE (MOdulo Sperimentale Elettromeccanico, Experimental Electromechanical Module) is a project intended to protect the city of Venice, Italy, and the Venetian Lagoon from flooding. The project is an integrated system consisting of rows of mobile gates installed at the Lido, Malamocco and Chioggia inlets that are able to temporarily isolate the Venetian Lagoon from the Adriatic Sea during high tides. Together with other measures such as coastal reinforcement, the raising of quaysides, and the paving and improvement of the lagoon, MOSE is designed to protect Venice and the lagoon from tides of up to 3 m.
The work is being carried out by the Consorzio Venezia Nuova[note 1] acting on behalf of the Ministry of Infrastructure and Transport – Venice Water Authority.[note 2] Construction began simultaneously in 2003 at all three lagoon inlets, and as of June 2013, 75% of the project has been completed.
- 1 Origin of the name
- 2 Context
- 3 Aim of the project
- 4 Chronology of the project
- 5 Operating principle
- 6 Construction
- 7 Mose in the Venice Arsenal
- 8 Specifications
- 9 Projections
- 10 Controversies
- 11 Alternative proposals
- 12 See also
- 13 Notes
- 14 References
- 15 External links
Origin of the name
Before the acronym was used to describe the entire flood protection system, MOSE referred to the 1:1 scale prototype of a gate that had been tested between 1988 and 1992 at the Lido inlet.
The name also holds a dual meaning, as MOSE is an allusion to the biblical character Mosè (Moses in English), who is remembered for the story where he parted the Red Sea.
MOSE is part of a General Plan of Interventions to safeguard Venice and the lagoon commenced in 1987 by the Ministry of Infrastructure through the Venice Water Authority (the Ministry's operational arm in the lagoon) and the concessionary Consorzio Venezia Nuova. The measures already completed or underway along the coastline and in the lagoon are the most important environmental defense, restoration, and improvement program ever implemented by the Italian State.
In parallel with work to construct MOSE, the Venice Water Authority and Venice Local Authority are raising quaysides and paving in the city in order to protect built-up areas in the lagoon from medium high tides (below 110 cm, the height at which the mobile barriers will come into operation). These measures are extremely complex, particularly in urban settings such as Venice and Chioggia where the raising must take account of the delicate architectural and monumental context. The measures to improve the shallow lagoon environment are aimed at slowing degradation of the morphological structures caused by subsidence, eustatism, and erosion due to waves and wash. Work is underway throughout the lagoon basin to protect, reconstruct, and renaturalise salt marshes, mud flats and shallows; restore the environment of the smaller islands; and dredge lagoon canals and channels.
Important activities are also underway to redress pollution in the industrial area of Porto Marghera, at the edge of the central lagoon. Islands formerly used as dumps are being secured; the industrial canals are being consolidated and sealed; and polluted sediments are being removed.
Aim of the project
The aim of Mose is to protect the lagoon, its towns and villages, its inhabitants and its historic, artistic and environmental heritage from floods, including extreme events. Although the tide in the lagoon basin is lower than in other areas of the world (where it may reach as high as 20 m), the phenomenon may become significant when associated with atmospheric and meteorological factors such as low pressure and the bora, a north-easterly wind coming from Trieste, or the Sirocco, a hot south-easterly wind. Those conditions push waves into the gulf of Venice. High water is also worsened by rain and water flowing into the lagoon from the drainage basin at 36 inflow points associated with small rivers and canals.
Floods have caused damage since ancient times and have become ever more frequent and intense as a result of the combined effect of eustatism (a rise in sea level) and subsidence (a drop in land level) caused by natural and man-induced phenomena. Today towns and villages in the lagoon are an average of 23 cm lower with respect to the water than at the beginning of the 1900s and each year, thousands of floods cause serious problems for the inhabitants and deterioration of architecture, urban structures and the ecosystem. For the entire lagoon area, there is also a constant risk of an extreme catastrophic event such as that of 4 November 1966 when a tide of 194 cm submerged Venice, Chioggia and the other built-up areas. Floods effects are further worsened due to greater erosion by the sea caused by human interventions to facilitate port activities (e.g. jetties, artificial canals); establishment of the industrial Porto Marghera area; and increased wash from motorized boats, which aggravate erosion of morphological structures and the foundations of quaysides and buildings. In the future, the high water phenomenon could, in fact, be further aggravated by the predicted rise in sea level resulting from global warming.
In this context, Mose, together with reinforcement of the barrier island, has been designed to provide protection from tides of up to 3 m. It will therefore be able to effectively protect the lagoon, even if the most pessimistic hypotheses come true, such as a rise in sea level of at least 60 cm (recent estimates from the IPCC (Intergovernmental Panel on Climate Change) predict a rise in sea level of between 18 and 59 cm during the next 100 years). Thanks to the management flexibility, Mose can be operated in different ways according to the characteristics and height of the tide. Given that the gates are independent and can be operated separately, all three inlets can be closed in the case of an exceptional event, the inlets can be closed one at a time according to the winds, atmospheric pressure and height of tide forecast, or again, each inlet can be partially closed.
Exceptional high waters have struck the city during the 20th century: the flood of November 1966 (194 cm), 1979 (166 cm), 2007 (160 cm), 1986 (158 cm), 1951 and 2012 (151 cm), 1936 and 2002 (147 cm), 1960 (145 cm), 1968 and 2000 (144 cm), 1992 (142 cm), 1979 (140 cm). All values were recorded at the Punta della Salute (Venice) station and refer to the 1897 tidal datum point.
Chronology of the project
Following the flood of 4 November 1966 when Venice, Chioggia and the other built-up areas in the lagoon were submerged by a tide of 194 cm, the first Special Law for Venice declared the problem of safeguarding the city to be of "priority national interest". This marked the beginning of a long legislative and technical process to guarantee Venice and the lagoon an effective sea defence system.
To this end, in 1975 the State Ministry of Public Works issued a competition call for tender, but the procedure was closed without a project being chosen from those presented as no hypothesis for action satisfied all the requisites. The Ministry therefore acquired the documents presented for the call for tender and passed them to a group of experts commissioned to draw up a project to preserve the hydraulic balance of the lagoon and protect Venice from floods (the "Progettone" of 1981).
A few years later, a further Special Law (Law no. 798/1984) emphasised the need for a unified approach to the safeguarding measures, set up the committee for policy, coordination and control of these activities (the "Comitatone" chaired by the President of the Council of Ministers and consisting of representatives of the competent national and local authorities and institutions) and entrusted design and implementation to a single body, the Consorzio Venezia Nuova, recognising its ability to manage the safeguarding activities as a whole. The Venice Water Authority – Consorzio Venezia Nuova presented a complex system of interventions to safeguard Venice (the REA "Riequilibrio E Ambiente", "Rebalancing and the Environment" Project) which included mobile barriers at the inlets to regulate tides in the lagoon. In this context, between 1988 and 1992, experiments were carried out on a prototype gate (MOdulo Sperimentale Elettromeccanico, hence the name Mose) and in 1989, a conceptual design for the mobile barriers was drawn up. This was completed in 1992 and subsequently approved by the Higher Council of Public Works, submitted to an Environmental Impact Assessment procedure and further developed as requested by the Comitatone. In 2002 the final design was presented and on 3 April 2003, the Comitatone gave the go-ahead for its implementation. The worksites were opened at the three lagoon inlets of Lido, Malamocco and Chioggia that same year.
Mose consists of rows of mobile gates at the three inlets which temporarily separate the lagoon from the sea in the event of a high tide. There will be a total of 78 gates divided into four barriers. At the Lido inlet, the widest, there will be two rows of gates of 21 and 20 elements respectively linked by an artificial island (the island connecting the two rows of gates at the centre of the Lido inlet will also accommodate the technical buildings with the system operating plant); one row of 19 gates at the Malamocco inlet and one row of 18 gates at the Chioggia inlet. The gates consist of metal box-type structures (20 m wide for all rows, with a length varying from 18.5 to 29 m and from 3.6 to 5 m thick), connected to the concrete housing structures with hinges, the technological heart of the system, which constrain the gates to the housing structures and allow them to move.
In normal tidal conditions, the gates are full of water and rest in their housing structures. When a high tide is forecast, compressed air is introduced into the gates to empty them of water, causing them to rotate around the axis of the hinges and rise up until they emerge above the water to stop the tide from entering the lagoon. When the tide drops, the gates are filled with water again and return to their housing. The inlets are closed for an average of between four and five hours, including the time taken for the gates to be raised (about 30 minutes) and lowered (about 15 minutes).
To guarantee navigation and avoid interrupting activities in the Port of Venice when the mobile barriers are in operation, a main lock is being constructed at the Malamocco inlet to allow the transit of large ships, while at the Lido and Chioggia inlets there will be smaller locks to allow emergency vessels, fishing boats and pleasure craft to shelter and transit.
It has been decided that the gates will be raised for tides more than 110 cm high. The competent authorities have established this as the optimum height with respect to current sea level, but the gates can be operated for any level of tide. The Mose system is also flexible. Depending on the winds, atmospheric pressure and level of tide, it can therefore oppose the high water in different ways – with simultaneous closure of all three inlets in the case of exceptional tides, by closing just one inlet at a time, or by partially closing each inlet, given that the gates are independent, for medium-high tides.
Construction of Mose was authorised by the "Comitatone" on 3 April 2003 and the worksites were opened that same year. Work began simultaneously and continues in parallel at the three inlets of Lido, Malamocco and Chioggia. Work on the structural parts (foundations, mobile barrier abutments, gate housing structures), associated structures (breakwaters, small craft harbours, locks) and parts for operating the system (technical buildings, plant) is now at an advanced stage. Currently about 4000 people are employed in the construction of Mose. As well as the worksites at the inlets, construction of the main components of Mose (the hinges, the technological heart of the system which constrain the gates to their housing and allow them to move, and the gates) is also proceeding. Restructuring of the buildings and spaces in the area of the Arsenal where maintenance of Mose and management of the system will be located is also underway.
The worksites at the lagoon inlets
Construction of Mose at the inlets necessitates complex logistical organisation of the worksites, located in a highly delicate environmental context so as to avoid interfering with the surrounding area as far as possible. The worksites have been set up on temporary areas of water in order to limit occupation of the land adjacent to the inlets and reduce as far as possible the effect on activities taking place there. Materials (for example, site supplies) and machines are also moved via sea to avoid overloading the road system along the coast. Since the worksites were opened, all work has been carried out without ever interrupting transit through the inlet channels.
Below is a description of the work underway and already completed at each inlet.
There will be two rows of mobile gates at the Lido inlet. To the north of the inlet (Cavallino-Treporti), a small craft harbour consisting of two basins communicating through a lock will allow small craft and emergency vessels to shelter and transit when the gates are raised. The sea-side basin was temporarily drained and sealed for use as a worksite to construct the gate housing structures for this barrier. Once the housing structures had been completed, the area was flooded with water to allow the housing structures (already positioned on the seabed) to be floated out. It is now an area of water again and will act as the sea-side basin of the small craft harbour. In 2013, installation and commissioning of the gates will begin and the main elements of the system will be installed for functional testing. This will also allow construction of the other barriers to be optimised. In 2013 the gate housing structures for the other row of barriers (currently under construction) will also be launched and positioned on the seabed. At the south of the inlet (San Nicolò), the existing breakwater has been enlarged and reinforced. At the centre of the inlet, a new island has been constructed to act as an intermediate structure between the two rows of mobile gates. This island will accommodate the buildings and plant for operating the gates (construction underway). In both inlet channels, the seabed in the areas where the gates will be installed has been reinforced. Outside the inlet, the 1000 m long curved breakwater has been completed.
Work is at an advanced phase to construct the lock which will allow the transit of large ships when the gates are raised, thus avoiding all interference with port activities during floods and with Mose in operation. A temporary worksite has been set up alongside the basin to fabricate the gate housing structures to be positioned on the sea bed (Malamocco and Lido San Nicolò rows and relative abutment structures). The seabed in the area where the gates will be installed has been reinforced. Outside the inlet, the 1300 m long curved breakwater designed to attenuate tidal currents and define a basin of calm water to protect the lock has been completed.
Work has been completed to construct a small craft harbour with double lock to guarantee transit of a large number of fishing vessels when the gates are in operation. The sea-side basin has been temporarily drained and sealed for use as a worksite to fabricate the gate housing structures. In the inlet channel, the seabed in the area where the gates will be installed has been reinforced. Outside the inlet, the 500 m long curved breakwater has been completed.
The hinges are the technological heart of the defence system. They constrain the gates to the housing structures, allow them to move and connect the gates to the operating plant. The steel gates consist of a male element (3 m high and weighing 10 tons) connected to the gate, a female element (1.5 m high and weighing 25 tons) fastened to the housing structure and an attachment assembly to connect the male and female elements. A total of 156 hinges (two for each gate) will be fabricated, together with a number of reserve elements. Fabrication is currently underway. The female elements for the gates in the Lido-Treporti barrier have already been installed on the housing structures now positioned in the sea bed in the inlet and invisible underwater.
Work progress and next stages
Between June and September 2012, the nine gate housing structures for the North Lido barrier were positioned and work is proceeding to connect the plant between one housing structure and the next. For the same barrier, the first gates and male hinge elements have been completed. In March 2013, four of these gates arrived at Marghera and were connected to the male hinge elements (the female element and attachment assembly are already installed on the housing structures positioned on the seabed in the inlet). Between June and July 2013, the four gates are positioned in the housing structures and attached to the female hinges by means of the male elements; in October the gates were operated for the first time to verify operation (the so-called "blank tests"). At the end of this year, the gate housing structures fabricated at the Malamocco inlet will be launched and positioned in the Lido inlet for the south side barrier.
During 2014, both barriers at the Lido inlet will be completed. At the same time, work will continue to launch and position the gate housing structures for the Malamocco and Chioggia inlets, to then proceed with installation of the gates and completion of the Mose system in 2016.
Mose in the Venice Arsenal
Activities for the control and maintenance of Mose and management of the lagoon system will be located in the Venice Arsenal, symbol of the trading and military might of the Serenissima. Numerous historical buildings, in a state of decay and abandonment for decades, have already been restored and functional reorganisation of the area to accommodate the new functions is underway. Restoration has enabled a heritage of extraordinary historical and architectural value to be safeguarded and allowed buildings to be recovered and re-utilised. The establishment of new functions there will give the Arsenal a new lease of life after years of abandonment and allow its reconversion as a place of innovation and production, with important economic repercussions for the city and local area.
In the gallery below, the historic Arsenal buildings before and after restoration and construction of infrastructure to accommodate the new functions.
- 4 the number of mobile barriers being constructed at the lagoon inlets (2 at the Lido inlet, 1 at Malamocco and 1 at Chioggia)
- 1.6 km the total length of the mobile barriers
- 18 km the total length of the worksites on land and at sea
- 78 the total number of gates
- 18.5 m x 20 m x 3.6 m length, width and thickness of the smallest gate (Lido–Treporti row)
- 29.5 m x 20 m x 4.5 m length, width and thickness of the largest gate (Malamocco row)
- 1 lock for large shipping at the Malamocco inlet enabling port activities to continue when the gates are in operation
- 3 small locks (2 at Chioggia and 1 at Lido-Treporti) to allow the transit of fishing boats and other smaller vessels when the gates are in operation
- 156 the hinges, two for each gate and a number of reserve elements
- 42 tons the weight of each hinge
- 3 m the maximum tide which the gates can withstand (to date, the highest tide has been 1.94 m)
- 60 cm the increase in sea level the Mose has been designed to cope with
- 30 minutes to raise the gates
- 15 minutes to lower the gates back into their housing structures
- 4/5 hours the average time the inlet will remain closed during a tidal event, including barrier raising and lowering times
- 4,000 people currently directly or indirectly employed
|This section is outdated. (June 2013)|
The main criticisms of the MOSE project, which environmentalists and certain political forces opposed since its beginning, relate to costs to the Italian State for construction, management, and maintenance, which are said to be much higher than alternative systems that the Netherlands and England have employed to resolve similar problems. In addition, according to those opposing MOSE, the monolithic integrated system is not "gradual, experimental and reversible" as required by the Special Law for the Safeguarding of Venice. Also there have been criticisms of the environmental impact of the barriers, not just at the inlets where complex leveling will be carried out (the seabed must be flat where the barriers will be installed) and the lagoon bed will be reinforced to accommodate the gates (which will rest on thousands of concrete piles driven underground for metres), but also on the hydrogeological balance and delicate ecosystem of the lagoon. The NO MOSE front also emphasises what could be a number of critical points in the structure of the system and its inability to cope with the predicted rise in sea level.
During the years, nine appeals have been presented. Eight were rejected by the TAR (Tribunale Amministrativo Regionale, regional administrative court) and the Council of State. The ninth, currently being examined by the Administrative Tribunal, was presented by Venice Local Authority and contests the favourable opinion of the Safeguard Venice Commission on the commencement of work in the Pellestrina site at the Malamocco inlet where part of the MOSE gate housing caissons will be made using processes which, according to the Local Authority, could damage a site of particular natural interest.
Regarding the environmental damage caused by current work, environmental associations have also requested the intervention of the European Union, as the activities affect sites protected by the Nature 2000 Network and by the European Directive on birds. Following the report of 5 March 2004 by the Venetian MP Luana Zanella, on 19 December 2005 the European Commission opened an infraction procedure against Italy for "pollution of the habitat" of the lagoon, given that the European Environmental Commission Directorate General considers that as it has "neither identified nor adopted – in relation to the impacts on the area 'IBA 064-Venice Lagoon' resulting from construction of the MOSE project – appropriate measures to prevent pollution and deterioration of the habitat, together with harmful disturbance of birds with significant consequences in the light of the objectives of article 4 of EEC Directive 79/409, the Italian Republic has not fulfilled the obligations deriving from article 4, paragraph 4, of EEC Directive 79/409 of the Council of 2 April 1979 on the conservation of wild birds". Specifying that the aim of the initiative is not to stop MOSE, the European Environmental Commission has called on the Italian Government to produce new information on the impact of the sites and the environmental mitigation structures. The Water Authority and Consorzio Venezia Nuova confirm that the work sites are temporary and will be completely restored at the end of the work.
Over the years, various proposals have been presented as an alternative to MOSE. Some propose quite different technological systems, others suggest technologies to improve the efficiency of the system of mobile gates. On the request of the Mayor of Venice, Massimo Cacciari, approximately ten of these projects were examined in 2006 by round tables of experts appointed by the individual responsible bodies, including the Higher Council of Public Works. In November 2006, negative assessments of the alternative proposals by these round tables led the Government to give the definitive approval for the MOSE project—the alternative proposals were deemed ineffective or inappropriate to guarantee the defence of Venice.
- Acqua alta
- Flood control
- Thames Barrier
- Oosterscheldekering, part of the Delta Works
- Saint Petersburg Flood Prevention Facility Complex
- The Consorzio Venezia Nuova is responsible for work to safeguard Venice and the lagoon delegated to the State on behalf of the Ministry of Infrastructure and Transport – Venice Water Authority, according to the provisions of the Special Law for Venice (Law no. 798 of 1984). Made up of a group of national and local construction companies, to carry out its task it has created a structure able to plan, organise and manage all phases of all activities.
- The Water Authority is heir to the historic office of the Serenissima set up in 1501. It is now the local organ of the Ministry of Infrastructure and Transport with direct primary responsibility for the safeguarding, safety and hydraulic protection of a large area including, in particular, the Venice lagoon.
- Page on the project at water-technology.net
- Law no. 171/1973, indicating the objectives and criteria for the measures to be implemented in the lagoon and defining the institutional parties involved and their relative responsibilities: the State for physical safeguarding and environmental restoration of the lagoon basin; the Veneto Region for water pollution abatement and the local Authorities of Venice and Chioggia for economic and social development, restoration and conservative improvement of urban structures
- Venice: duels over troubled waters
- Keahey, John (2002). Venice against the sea : a city besieged (1. ed. ed.). New York: St. Martin's Press. ISBN 978-0-312-26594-6.
|Wikimedia Commons has media related to MOSE Project.|
- www.salve.it is the website dedicated to activities to safeguard Venice and the lagoon implemented by the Italian State, with a specific section on Mose.
- www.magisacque.it is the website of the Venice Water Authority, a local branch of the Ministry of Infrastructure and Transport whose responsibilities include management, safety and hydraulic protection of the Venice lagoon.
- www.consorziovenezianuova.it is the website of the Consorzio Venezia Nuova, the Ministry of Infrastructure and Transport – Venice Water Authority concessionary for implementing the measures to safeguard Venice and the lagoon delegated to the State.
- www.comune.venezia.it – City of Venice official website.