Adjust the three degrees of freedom — movable length (x1), gate height (x2), and closure duration (x3) — to see how stakeholder metrics respond in real time. The sliders mirror the GA notebook used in PBED sessions.
Design Controls
0–1600 m. Represents how much of the 1.6 km inlet span is composed of movable gates rather than fixed structure.
Current: 800 m
1–10 m. Taller gates improve safety but are heavier, more visible, and harder to maintain.
Current: 5.50 m
0.5–5 h. Short closures favour water exchange and port access; long closures ease operations but frustrate shipping and ecology.
Current: 2.75 h
Design Variables in the MOSE Barrier Project
Within the MOSE barrier system, several design variables determine how the structure performs and interacts with its environment. Each variable represents a design choice that influences both the technical performance and the economic feasibility of the barrier. Some solutions may be more expensive but deliver higher reliability or reduced environmental impact, while others prioritise cost efficiency or faster operation. Understanding these trade-offs is essential when optimising the system's overall design.
In our project we focus on three primary design variables that you can explore with the sliders:
The length of the MOSE barrier.
The height of the MOSE barrier.
The closure time of the MOSE barrier.
1. Length of the MOSE barrier
In the actual MOSE system, barriers span the three inlets of the Venetian Lagoon for a combined length of approximately 1,600 metres. The length directly affects the construction cost, the amount of structure visible above the water, and the openness of the lagoon to the Adriatic Sea.
For our study we vary the barrier length between 1 metre and 1,600 metres. The upper bound reflects the full inlet length; any additional length would extend beyond the lagoon openings and is therefore not considered.
2. Height of the MOSE barrier
The current MOSE gates are engineered to resist tides up to roughly N.A.P. +3 metres. Barrier height determines the maximum water level the system can withstand before overtopping occurs. Increasing the height improves resilience against extreme events, but it also raises construction complexity, cost, and visual impact on the lagoon landscape.
In the analysis the gate height is treated as a variable between 1 and 10 metres so that we can examine how taller or shorter gates influence performance and stakeholder preferences.
3. Closure time of the MOSE barrier
At present it takes about 32 minutes (≈0.5 hours) to close a MOSE gate completely. Closure time governs both operational responsiveness and navigation impact. Faster closures enhance protection during sudden storm surges but require more powerful mechanical systems and higher energy consumption. Longer closure times reduce mechanical stress, yet they increase exposure to rapidly rising water levels and keep shipping channels closed for longer.
We therefore allow closure time to range between 0.5 hours and 3 hours, capturing the trade-off between efficiency, safety, and operational practicality.
Influence of Design Variables on MOSE Barrier Performance
The design variables of the MOSE barrier affect several key performance aspects of the system. Based on input from stakeholders (see the Stakeholders page), the following aspects have been identified as most important for evaluating the effectiveness and feasibility of the barrier:
Initial construction cost
Lifetime maintenance cost
Sightline score
Navigation accessibility
Water quality score
Residual overtopping risk
Each of these aspects is influenced by the three main design variables: the length (L), height (H), and closure time (T) of the barrier.
Initial construction cost
The initial construction cost represents the total investment required to build the MOSE barrier. This aspect is crucial to stakeholders, as the project must remain financially feasible while still providing adequate protection.
In our model, the initial construction cost depends directly on the length, height, and closure time of the barrier. A longer and taller barrier increases both material and mechanical costs, while a shorter closure time requires more powerful systems, making the design more expensive. Conversely, a shorter barrier results in lower construction costs but requires additional traditional embankments, which are cheaper to build.
The cost is estimated using the following equation:
The lifetime maintenance cost represents the total cost of maintaining the MOSE barrier system throughout its operational lifespan. This includes periodic inspections, mechanical maintenance, corrosion protection, and replacement of worn components. From a stakeholder perspective, this aspect is vital to ensure the long-term reliability and economic sustainability of the flood protection system.
In our model, this cost is primarily determined by the length (L), height (H), and closure time (T) of the barrier. Longer and higher barriers require more maintenance due to their larger surface area and mechanical complexity, while a shorter closure time increases the operational stress on moving components, leading to higher upkeep costs over time.
The lifetime maintenance cost is calculated using the following equation:
The sightline score represents the visual impact of the MOSE barrier on the surrounding landscape and views of the Venetian Lagoon. Stakeholders identified this as an important factor for preserving the aesthetic value and cultural heritage of the area. A design with taller or more extensive barrier sections can obstruct views, whereas shorter or fewer movable elements maintain a more open and visually appealing horizon.
The sightline score depends on the length (L) and height (H) of the barrier. A larger proportion of movable sections contributes positively to visibility, while higher barriers reduce it.
The score is estimated using the following simplified equation:
This relationship captures the balance between movable and fixed parts: more movable sections improve visibility, while higher structures decrease it. The final score is limited between 0 and 10, ensuring that extreme values remain within a realistic range.
Navigation accessibility
The navigation accessibility score reflects how easily ships and vessels can move in and out of the lagoon while the barrier system is operational. This factor is crucial for maintaining economic activity and maritime transport, both of which are vital to Venice.
Two variables play the largest role: The length (L), more movable sections mean fewer obstructions to navigation. The closure time (T), faster closures reduce the total time the barrier remains shut, minimizing disruption for ships.
The navigation accessibility score is calculated as:
Snavigation = (L / 1600) × 10 − (10 / 7) × T
Here, longer movable sections and shorter closure times result in better accessibility. The score is constrained between 0 and 10, ensuring realistic operational boundaries.
Water quality score
The water quality score represents how the operation of the MOSE barrier affects the exchange of water between the lagoon and the Adriatic Sea. This exchange is critical for maintaining ecological balance and water quality.
A longer closure time reduces this exchange, causing water stagnation and degradation in quality. Conversely, a system with more movable sections and faster closing cycles allows for greater flexibility, improving circulation and water renewal.
The score is given by:
Swater = (L / 1600) × 10 − (10 / 24) × T
In this formula, increasing the barrier length improves the score (as more controlled openings exist), while increasing closure time decreases it (as the lagoon remains closed for longer). Like other indicators, the score is scaled between 0 and 10.
Residual overtopping risk
Residual overtopping risk measures the remaining probability that water levels will exceed the barrier height during extreme storm events. It depends mainly on the gate height: taller gates provide exponentially stronger protection, though they increase cost and visual impact.
Rovertopping = 0.65 × e−0.35 × (H − 1)
H represents the barrier height in metres; the risk is scaled between 0 and 10 for interpretation.
Metric Feedback
Initial construction cost
Preference: 95 / 100
€1.02B
Annual maintenance cost
Preference: 100 / 100
€10.00B
Sightline score
Preference: 59 / 100
5.91
Navigation accessibility
Preference: 11 / 100
1.07
Water quality score
Preference: 39 / 100
3.85
Residual overtopping risk
Preference: 87 / 100
13.5%
Preference Curves (notebook derived)
Each curve is the PCHIP interpolation from the mose_3x5_corrected.ipynb notebook and captures how stakeholders score a performance aspect as the underlying metric shifts. The red marker shows the preference score for the current design.