"Acqua Alta" and the need for Mo.S.E. project

"Acqua Alta" and the need for Mo.S.E. project: Managing the coastal flood in Venice

Godlewski, Gabriela (TU Delft Civil Engineering and Geosciences)
Caporalini, Luisa (TU Delft Civil Engineering and Geosciences)
Deuss, Bram (TU Delft Civil Engineering and Geosciences)

Jonkman, Sebastiaan N. (mentor)
Antonini, A. (mentor)
Diaz-Loaiza, Andres (mentor)
Houwing, E.J. (mentor)

Delft University of Technology

Multidisciplinary Project

2020-05-18

The city of Venice has been prone to flooding throughout its history. However, flooding has recently been occurring more often than before. As a result, engineers have collaborated to come up with a potential solution to the flooding. This solution, a mobile barrier known as the Experimental Electromechanical Module (Modulo Sperimentale Elettromeccanico, or Mo.S.E.) has been in progress for quite some time now and is therefore still not functional. On 12 November 2019, an extreme high water level event occurredwith the second highest recorded water level in history. The flooding event should have been prevented by the construction by a flap gate storm surge barrier, a project started after the 1966 historical high water event, which takes the name of Mo.S.E. project. In this paper, the 2019 event is analyzed, investigating the causes of the event and the design criteria of the Mo.S.E. barrier project in terms of its structure, construction process and completion state at the time of the event.The meteorological and hydrological causes of the 12 November 2019 is studied to better understand what caused the event. If the causes of an event are understood, a solution to similar future events can be more easily determined. Historic waterlevel data is used to better understand the hydraulic conditions within the Venice Lagoon. Existing research projects that utilized similar data are studied to estimate the return periods considered in the design of the Mo.S.E. barrier. The return period for the 12 November event (187 cm) was found to be about 130 –140 years. The return period for the water level at which the Mo.S.E. barrier is designed to be fully closed (110 cm) is 5 –7 years. The effects of climate change and subsequent eustacy are also analyzed to determine how this would affect the return periods of both the 12 November 2019 event and the barrier closure level. Analysis of estimated future return period data predicted thatthe return period range for the 12 November event would decrease from 130 –140 years to50 –100 years while the return period range for the Mo.S.E. barrier closure would decrease from 5 –7 years to 2 –5 years. An estimation of the flooded buildings and roads is made. Surface elevation data is compared with the water level of the November 2019 flood event. In this way information is gained about what areas were flooded. By using downloaded from Open Street Maps, information about all buildings and roads, including their location, are obtained. Analyzing this data results in information about what buildings and roads are flooded. These results, together with numbers of damage per flooded object, are used to make an estimation of the total direct damage due to the flood event. The estimated total direct damage amounts to €870 million.The estimated damage to cultural heritage amounts to €244 million. Also, the case was investigated in which the Mo.S.E. barrier would have been operational during the November 2019 flood event. If the barrier had closed, the total direct damage would have been€257 million.Conclusively, an analysis of the management system of the Riequilibrio E Ambiente (REA, Lit. Rebalance and Environment) mega-project and the Mo.S.E. project is conducted to visualize the main failures and delay causes which lead to the circumstances of incompletion of the barrier at the time of the 2019 flood event. Through a careful analysis of the main events and technical problems encountered throughout the planning and construction of the barrier, the leading cause of delay is found to be political corruption, along with uncareful definition of project objectives and extreme levels of project complexity. Currently, the completion of the storm surge barrier is scheduled to be at the end of 2021. In 2019, the construction of the barrier wasfound to be completed at its 94%, signifying an 8-year delay past the original completion date of 2012, which was determined at the begging of the construction works in 2005. The Mo.S.E. barrier project is merely one part of a much larger mega-project designed for the safeguard of Venice which was meant to be completed in 1985. While the Mo.S.E. barrier is delayed almost 8 years, the entire project is delayed by a total of 26 years.It is recommended to direct further researches to future impact, considering climate change, and the amount of damage for certain return periods and the impact of the Mo.S.E. barrier on this last. Hence data collection making damage estimations more accurate, internal corruption prevention and management within large infrastructure works and feasible optimizations solutions to apply to the Mo.S.E. barrier in order to face sea level ris

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© 2020 Gabriela Godlewski, Luisa Caporalini, Bram Deuss