April 23, 2019 Insights

Protecting Venice’s Lagoon from Acqua Altissima

Erin Flannery Keith

Venice’s piazzas seem always ready for acqua alta––the routine flooding phenomenon that occurs at during particularly high tides. Municipal workers stack platforms around the city and quickly arrange them into elevated sidewalks when the Venetian lagoon’s waters lap over low banks and seep up through paving stones. Stepping into Saint Mark’s Basilica, a lofty 40 centimeters above sea level, one smells and sees that water has been creeping into the marble and mosaics for centuries. The flooding is becoming more serious and frequent––less an occasional annoyance and more an existential threat to Venice’s structures and natural environment. On October 31 and November 1, 2018, a storm surge deluged the city in 61 inches of water. Jason Horowitz, In Venice Floods, Tourists Frolic as Locals Fear for Treasures, N.Y. Times, Nov. 2, 2018, at A7. Venice, like many other coastal cities, urgently needs to combat climate-change exacerbated sea level rise and storm surges and protect its ecosystems, cultural heritage, and residents. An enormous system of mobile underwater floodgates called the Modulo Sperimentale Elettromeccanico, or Experimental Electromechanical Module (MOSE), was debated for decades and construction began in 2003. MOSE would comprise three massive gates that would mechanically rise at three barrier island entrances to Venice’s lagoon during flood events. Due to a labyrinthine succession of governmental entities with primary jurisdiction, an unwieldy number of other required approvals, and official corruption, the MOSE project is years behind schedule. The project recently missed its latest projected launch date of December 2018 and, if functioning, could have lessened the fall 2018 catastrophic acqua altissima (very high water). As a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site (WHS), consider Venice as cultural charismatic megafauna: perhaps other countries and cities can learn from the MOSE experience in planning for infrastructure projects to protect sites important to global heritage from the effects of climate change.

Venice has been inextricably tied to its relationship to and management of water since the city’s founding in the fifth century. Early Venetians settled on the lagoon’s marshy islands and later began building an improbable but enduring city on platforms sitting on foundations of millions of wooden stakes driven into the lagoon. This design created a city of about 120 islands connected by narrow canals. The Venetian lagoon also includes long-settled wetland islands away from the city core but within the lagoon bounded by barrier islands. Likely because of the Roman law tradition of managing water as a public resource, since at least the 16th century Venice has had governmental entities whose sole purpose was governing activities in and around the lagoon and canals. The Republic of Venice established the Magistrato alle Acque in 1501, a government department with authority to manage and secure Venice’s lagoon and tributary rivers, including land reclamation projects and irrigation management. When another Venetian Republic agency was formed in 1545 to manage irrigation and water quantity overall, the Magistrato alle Acque retained specific authority over irrigation projects impacting the lagoon. From 1600 to 1604, the Magistrato alle Acque oversaw projects that diverted the Brenta, Sile, Piave, and Po Rivers so that sediment would not fill the lagoon and impede commercial navigation. However, by changing the region’s natural accretion and avulsion cycles, the diversions caused Venice to begin sinking and changed wetland morphology––a process that has continued for centuries and has magnified recent sea level rise. After falling to Napoleon in 1797, control over Venice traded hands until it became part of the newly formed unified Italy in 1866. The Magistrato alle Acque became an arm of the new national Ministry for Infrastructure and Transport in 1907 and retained its unique Venetian jurisdiction.

Following historic floods in 1966, the Italian Parliament passed the Special Law for Venice, Legge 16 Aprile 1973, n. 171, to authorize flood control planning. Parliament later passed additional legislation to establish the Consortzio Venezia Nuova (CVN), a quasigovernmental agency and construction consortium to which the Ministry of Infrastructure and Transport delegated the jurisdiction of the Magistrato alle Acque. See Legge 5 Febbraio 1992, n. 139. These laws gave CVN the charge and authority to plan and oversee construction of the MOSE barriers.

In addition to following the Italian laws specifically governing the Venetian lagoon, CVN must adhere to overall Italian environmental law requirements. Pursuant to Italy’s Code of Environmental Law, the Ministry of the Environment and Protection of Land and Sea must issue environmental impact assessments (EIAs) that identify, describe, and evaluate environmental factors and alternatives before project work can commence. Decreto Legislativo n. 152/2006. EIAs expire after five years and must be reissued. This law also provides rights of action in regional administrative courts for challenges to environmental administrative actions. Environmental groups have unsuccessfully challenged the lack of or deficiencies in EIAs related to MOSE nine times in court.

Two UNESCO conventions recognize and protect Venice’s built and natural environment, add considerations for projects that could adversely affect Venice’s cultural and environmental resources, and provide funding opportunities for projects to maintain Venice’s status as a WHS. Part of Venice’s lagoon is designated as a Wetland of International Importance under the Convention on Wetlands of International Importance especially as Waterfowl Habitat, Feb. 2, 1971, U.N.T.S. 14583 (effective in Italy April 14, 1977) (Ramsar Convention). Venice’s lagoon was added to the Ramsar list in 1989. At 550 square kilometers, the Venice lagoon is the largest wetland system in the Mediterranean basin. Italy agreed to uphold the convention’s wetlands management and planning principles, including “compensat[ing] for any loss of wetland resources” within the Ramsar-designated wetland area. See Ramsar Art 4. § 2.

Venice is uniquely vulnerable to inundation. Continuous groundwater pumping and unmitigated port dredging accelerated city subsidence and wetland destruction in the twentieth century. Situated in the northwest corner of the Adriatic Sea, Venice also receives the brunt of storm surges fueled by intense cross-basin winds. A new study flags its dramatic flood vulnerability: 97 percent of the area of the Venice WHS is vulnerable to flooding due to elevated sea levels––the highest percentage of area of any other Mediterranean WHS. See Lena Reinmann et al., Mediterranean UNESCO World Heritage at Risk from Coastal Flooding and Erosion Due to Sea-Level Rise, 9 Nature Communications 2 (Oct. 16, 2018). The study also found that Venice is the Mediterranean WHS with the highest overall likelihood of flooding. In a global region with the highest number of ancient WHSs at risk from climate-change related sea level rise, Venice is the worst of the worst.

With a diminished area available to provide erosion control, sediment transport, and flood control, it becomes even more important to ensure that infrastructure projects in the lagoon wetland area also include mitigation and compensation measures during construction and deployment. In earlier project phases, CVN installed a variety of wetlands restoration projects during MOSE construction that will also help compensate for the tidal flow alteration when the barriers are up, including constructing new wetland habitats and planting vegetated barriers to decrease erosion. However, environmental groups continue to comment on the deficiencies of the EIAs for various MOSE stages. Recently, one group commented that there was no EIA authorizing a new stage of MOSE construction at one of the inlets and that plans for that stage did not adequately provide for beach nourishment or other mitigation. See Comments submitted by Italia Nostra Venezia July 23, 2018, available at www.italianostravenezia.org/wp-content/uploads/2018/07/Osservazioni-unitarie-INV-VC-EV-CAAL-WWFV-LIPUV.pdf.

Under UNESCO’s World Heritage Convention, Venice and its lagoon are designated as a WHS. See Convention Concerning the Protection of the World Cultural and Natural Heritage, Nov. 16, 1972, 27 U.S.T. 37, 1037 U.N.T.S. 151. UNESCO designates WHSs based on their Outstanding Universal Value (OUV) and designated Venice and the lagoon in part because they “represent an outstanding example of a semi-lacustral habitat which has become vulnerable as a result of irreversible natural and climate changes. In this coherent ecosystem where the muddy shelves (alternately above and below water level) are as important as the islands, pile-dwellings, fishing villages, and rice fields need to be protected no less than the palazzi and churches.” See World Heritage Committee, Decision CONF 005 VII.A, Venice and Its Lagoon, Dec. 1987.

State parties must maintain an adequate legal framework to protect a WHS’s OUV and are responsible for site management, planning, and preservation. In Italy, the Ministry of Cultural Heritage and Activities and Tourism oversees WHS planning pursuant to the Code of the Cultural and Landscape Heritage. Decreto Legislativo no. 42/2004. WHS management plans must comply with Decreto Legislativo no. 77/2006. Venice’s most recent plan “places protection of the physical structure of the lagoon at the basis of the protection of Venice, combating the erosion process and simplifying the complex lagoon habitat systems still present, and at the same time protecting Venice from wave motion and high tides, both by installing local protection systems, and by temporarily closing the lagoon entrances.” See Venice and Its Lagoon World Heritage Site Management Plan 2012–2018, Department for Territorial Development, at XI.

In its most recent evaluation, UNESCO appears concerned that this management plan does not adequately incorporate UNESCO’s Policy on the Impacts of Climate Change on World Heritage Properties. See World Heritage Committee, Decision 41 COM 7B.48, Venice and its lagoon (Italy) (C 394), June 2017. If UNESCO determines that Italy’s December 2018 management plan does not include climate adaptation considerations, concrete plans for the completion of MOSE, and “a detailed roadmap forward . . . to maintain the long tem OUV of the property,” UNESCO may consider placing Venice and Its Lagoon on the List of the World Heritage in Danger. Id. at paras. 10 and 12.

Italy now estimates that MOSE will be fully operational by 2021. See State of Conservation Report by the State Party, World Heritage Property Venice and Its Lagoon at 91, Dec. 14, 2018. However, there are plenty of reasons to doubt that estimate, because MOSE already is about a decade behind schedule due to turbulent management. CVN became riddled with corruption related to MOSE construction bribes, and then-Prime Minister Matteo Renzi removed its two top officials and disbanded CVN in 2014. The Italian Anti-Corruption Authority took over CVN’s responsibilities in 2014, and then CVN’s jurisdiction was transferred to the Municipality of Venice. The Magistrato alle Acque’s DNA is still part of the agency that hopefully will bring MOSE over the finish line. Culturally and ecologically vulnerable WHSs need particularly careful management and planning for climate resilience. Perhaps one primary agency could oversee streamlined resilience planning, public participation, and project authorization and report back to UNESCO on compliance with World Heritage Convention and Ramsar Convention expectations. Fifty-two years have passed since the Special Law for Venice that initiated flood control planning. Venice does not have 52 more years to save itself if it does not efficiently complete MOSE and deploy more nature-based solutions to combat sea level rise and acqua altissima.


Erin Flannery Keith

Ms. Keith is an attorney-advisor in the U.S. Environmental Protection Agency’s Region 1 Office of Regional Counsel in Boston and is a member of the Natural Resources & Environment editorial board. The views expressed here are those of the author only and do not necessarily reflect those of the United States or U.S. EPA. She may be reached at eflannerykeith@gmail.com.