MOSE Project

Aerial view of the MOSE Project north of Lido

The MOSE Project (Modulo Sperimentale Elettromeccanico, Experimental Electromechanical Module) is intended to protect the city of Venice, Italy from floods. The project is an integrated defense system consisting of rows of mobile gates which are intended to isolate the Venetian Lagoon from the Adriatic Sea when the tide rises above 110 cm. The barriers will protect the city from water levels up to 3 m (9.8 ft). Together with complementary measures such as coastal reinforcement, raising quaysides and paving, and improving the lagoon environment, these barriers will protect the city from extreme events such as floods as well as morphological degradation. Work began in 2003 at the three lagoon inlets of Lido, Malamocco and Chioggia through which the tide ebbs and flows. The project is being executed by engineers at FIAT.^{[citation needed]}

In 2006, the incoming government of Romano Prodi announced that the project was "under review" for budgetary reasons. However, the project was reinstated the following year, and in January 2008 it was reported to be 63% complete and projected to open on schedule in 2014.

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 di Venezia inlet. The name MOSE also plays on the Italian name for Moses, Mosè, who divided the waters of the Red Sea. Mose was also rescued from water drowning by a pharao's daughter.

Context

Map of the Venetian Lagoon

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 programme ever implemented by the Italian State.^{[citation needed]}

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

The MOSE project is intended to protect Venice and other towns and villages in the lagoon from the high waters which, in autumn, winter and spring, have caused damage since ancient times. 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 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.

The greater frequency and intensity of high water is also associated with other natural and artificial causes which have altered the hydraulic and morphological structure of the lagoon, such as subsidence and eustatism (during the 20th century land in the lagoon dropped by 23 cm with respect to mean sea level[2]); greater erosion by the sea, due to 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 addition to tackling these problems, the MOSE Project (and the other defence measures) have been designed to accommodate the expected rise in sea level caused by global warming. The mobile barriers can protect the lagoon effectively for a sea level rise up to 60 cm.

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

The need to protect Venice and other built-up areas in the shallow lagoon was recognized following the devastating flood of 4 November 1966. That day, driven by a strong sirocco wind, the tide reached a height of 194 cm above the tidal datum, the highest ever recorded in the history of Venice. The tidal event began on the night of 3 November. On the morning of the 4th, instead of withdrawing as it would under normal conditions, the water continued to rise throughout the day and flooded the entire city. That evening the wind dropped, and the water started to ebb. At the same time, a violent sea storm devastated the beaches and broke the seawall at a number of points along the coast, requiring Pellestrina to be evacuated.

By the Special Law of 1973, the Italian State declared Venetian flooding to be of "priority national interest." In the early 1970s the CNR promoted a competition of ideas, and subsequently the Ministry of Public Works called for tender, in 1980 acquiring the projects presented. The six project proposals were passed to a commission of seven hydraulic engineers for evaluation and a feasibility study. Known as the "Progettone" and presented in 1981, the study proposed a combination of fixed barriers at the inlets and mobile defence structures. The proposal triggered a long debate involving the institutions; scientific, political, and cultural worlds; media; and residents.

The strategies and criteria to be adopted for protecting the city were defined by the second Special Law on Venice in 1984. This set up a Committee for Policy, Coordination and Control (known as the "Comitatone", chaired by the Prime Minister and consisting of the relevant institutions at national and local level) and authorised the Ministry of Public Works to proceed with granting of a single concession to be agreed by private negotiation. The need, reiterated in a 1982 document from Venice Local Authority, was for speed, but above all adopting a unified and organic approach given the complex and delicate context of the lagoon basin by entrusting the work to a single body with the right qualifications. The Water Authority entrusted the Consorzio Venezia Nuova, a pool of about fifty companies set up in 1982, to design and construct protection for the city.

In 1989, after four years of surveys, studies, and analyses of the numerous systems of mobile barriers, the Consorzio Venezia Nuova presented a complex proposal known as the REA Project (Riequilibrio E Ambiente, "Rebalancing and the Environment"). It included the Conceptual Design for the Mobile Barriers at the Lagoon Inlets, the birth of MOSE. After experiments on the prototype and a number of modifications, the new preliminary design for the mobile barriers was approved by the Higher Council of Public Works in 1994. After also examining other flood defence projects, the body approved the MOSE system.

In 1997, the Water Authority and Consorzio Venezia Nuova presented the environmental impact study (EIS) which in 1998 was approved by a commission of five international experts appointed by Prime Minister, Romano Prodi. The same year, the design for mobile barriers was disapproved by the Ministry of the Environment Environmental Assessment Commission. On the request of the Committee for Policy, Coordination and Control, MOSE was developed further. In 2001, at the end of the Environmental Impact Assessment procedure, the Council of Ministers, chaired by the Prime Minister, Giuliano Amato, approved development of the final design and set several conditions. In 2002, the Consorzio Venezia Nuova presented the final design, which incorporated requests of the Ministry of Transport and Port Authority—curved breakwaters in front of the lagoon inlets and a lock for large shipping at the Malamocco inlet. In 2002 the CIPE (Interministerial Committee for Economic Programming) allocated €453 million for the first tranche of work on the MOSE system, for the years 2002 through 2004.

In 2003, after approval by the Committee for Policy, Coordination and Control, Prime Minister Silvio Berlusconi laid the first stone and officially opened the first MOSE work sites. By March 2008, 40% of the work underway in parallel at all three inlets had been completed and €2,443 million had been attributed out of a total cost for the MOSE system of €4,272 million.

On 31 January 2008, the CIPE approved financing of the fifth tranche of €400 million, enabling construction to begin on the caissons, the most important and final part of the project.

If funding continues to arrive regularly, the work is expected to be completed in 2014.

Work sites and complementary structures

Work on MOSE is proceeding in parallel at all three inlets where 700 people are currently employed. These will be joined by a further 700 when the sites to construct the caissons on which the gates will rest are opened. Work to construct the mobile barriers was preceded by implementation of a series of measures to protect the coasts of Jesolo, Cavallino, Lido, Pellestrina, Sottomarina and Isola Verde from violent sea storms. This work included widening and reconstructing 45 km of beach, restoring 8 km of dunes and reinforcing 11 km of jetty and 20 km of the Istrian stone seawall (the "Murazzi"), which protects the most fragile parts of Venice's beaches. Outside the inlets of Malamocco and Chioggia, two "crescents" (curved breakwaters) were constructed to attenuate tide levels and protect the locks.

Operation of the gates

MOSE section scheme

MOSE is a system of retracting, oscillating buoyancy flap gates that complies with indications given in 1982 (vote no. 209 of the Higher Council of Public Works [3]) that the barriers must not alter water exchange between the sea and lagoon in order to preserve lagoon morphology and water quality; must not obstruct navigation, interfere with port activities or fishing; and must not alter the landscape. In normal conditions, the gates, are full of water and rest in prefabricated concrete caissons on the reinforced seabed. When a tide higher than 110 cm is forecast, compressed air expels the water from the gates and they rise, rotating around the axis of the hinges until they emerge from the water, temporarily isolating the lagoon from the sea and stopping the tidal flow. The gates reach the raised position in about 30 minutes and take about 15 minutes to retract. They are large metal boxes, 20 m wide x 20 to 30 m long x about 5 m thick.

The responsible bodies have agreed that, at current sea levels, the barriers will operate at a sea level of 110 cm, but the MOSE System could be used at lower levels. The system can be used in various ways, according to the winds, pressure and level of the tide, with selective or partial closure of the inlets.

A total of 78 gates divided into four rows will be installed to protect the three inlets: two rows of 21 and 20 gates at the Lido-San Nicolò inlet, the widest, connected by an artificial island; one row of 19 gates at the Malamocco inlet and one row of 18 gates at the Chioggia inlet. To guarantee navigation while the mobile barriers are in operation, three locks are being constructed to allow the transit of vessels (large ships at Malamocco, pleasure, emergency and fishing boats at Lido and Chioggia).

At the end of work, the consortium which has designed and constructed MOSE will be in charge of management and maintenance of the system for four years, then for a further 10 years it will be responsible for its operation and for all the other public works.

Usage

The project consists of a system of 78 mobile barriers designed to protect the three entrances to the Venetian Lagoon. The barriers will stay on the seabed until high tides and storms are forecast. They will then be floated, blocking the sea from the lagoon and effectively reducing high water levels.

Projections

The MOSE project has a budget of € 4.7 billion and it is planned to be completed by 2014. As of January 2008, the project is reported as 63% complete and projected to open on schedule in 2014

Controversy

The project has met resistance from environmental and conservation groups such as Italia Nostra, and the World Wide Fund for Nature commented negatively on the project.

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.

Appeals

During the years, nine appeals have been presented. Eight were rejected by the TAR 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".[5] 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.

Alternative proposals

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 alternate 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.

See also

• Flood
• Flood control
• Floodgate
• Thames Barrier
• Oosterscheldekering, part of the Delta Works
• Saint Petersburg Flood Prevention Facility Complex

Sources

• "Venice Against the Sea: A City Besieged" By John Keahey (Thomas Dunne Books, St. Martin's Press, March 2002, ISBN 978-0-312-26594-6)
• Techcentralstation.com
• NOVA Sinking City of Venice
• mose-project (water-technology.net)