Matteo Volpato

Bio: Matteo Volpato is an academic researcher from University of Padua. The author has contributed to research in topics: Wave height & Storm. The author has an hindex of 3, co-authored 4 publications receiving 40 citations.

Flooding of Piazza San Marco (Venice): Physical Model Tests to Evaluate the Overtopping Discharge

Abstract: This paper aims at evaluating the wave overtopping discharge over the pavement of “Piazza S. Marco” (Venice) in order to select the best option to mitigate the risk of flooding of the Piazza and to protect the monuments and historic buildings, e.g., the “Basilica S. Marco”. In fact, the MO.S.E. (MOdulo Sperimentale Elettromeccanico) system is designed to keep the water level below a certain value, for the safety of the lagoon, but it does not guarantee the defence of the Piazza, where flooding is still possible, being its pavement locally much lower than the maximum expected water level. To completely defend the Piazza, specific additional works are planned to prevent the back-flow through the natural drainage system (now the primary pathway) or by filtration or by overtopping. This paper investigates on the overtopping mechanism, under conditions compatible with a fully operational MO.S.E. system, through 2-D experiments. The pavement of the Piazza is gently sloping towards the masonry quay which, in some parts is formed by 5 descending steps, and in some other parts, is just a vertical wall. Close to the “Marciana” Library, a critical part is present, with a slightly lower crest freeboard. In total, three cross-sections were examined in the 36 m long wave flume of the Padova University. The test programme includes 10 irregular wave attacks and three different water levels. The test results differ considerably from the results of the available formulas, since the investigated cross-sections by far exceed their range of applicability. The presence of the steps affects only the reflection coefficient rather than the overtopping discharges. In general, if the waves incident to the Piazza are higher than 40 cm, which is a possible scenario, some other adaptation works must be considered, such as the pavement rise, temporary barriers or the reduction of the waves impacting the quay through, for instance, floating breakwaters.

Hydraulic Experiments on a Small-Scale Wave Energy Converter with an Unconventional Dummy Pto

Abstract: This paper investigates on a Wave Energy Converter (WEC) named Energy & Protection, 4th generation (EP4). The WEC couples the energy harvesting function with the purpose of protecting the coast from erosion. It is formed by a flap rolling with a single degree of freedom around a lower hinge. Small-scale tests were carried out in the wave flume of the maritime group of Padua University, aiming at the evaluation of the device efficiency. The test peculiarity is represented by the system used to simulate the Power Take Off (PTO). Such dummy PTO permits a free rotation of two degrees before engaging the shaft, allowing the flap to gain some inertia, and then applying a constant resistive moment. The EP4 was observed to reach a 35% efficiency, under short regular waves. The effects, in terms of coastal protection, are small but not negligible, at least for the shortest waves.

Effect of Mo.S.E. Closures on Wind Waves in the Venetian Lagoon: In Situ and Numerical Analyses

Abstract: In the Venetian lagoon, the storm surge barriers (Mo.S.E. system) are crucial to prevent urban flooding during extreme stormy events. The inlet closures have some cascading effects on the hydrodynamics and sediment transports of this shallow tidal environment. The present study aims at investigating the effects of the Mo.S.E. closure on the wind-wave propagation inside the lagoon. In situ wave data were collected to establish a unique dataset of measurements recorded in front of San Marco square between July 2020 and December 2021, i.e., partially during the COVID-19 pandemic. Ten storm events were analyzed in terms of significant wave heights and simultaneous wind characteristics. This dataset allowed for validating a spectral wave model (SWAN) applied to the whole lagoon. The results show that the floodgate closures, which induce an artificial reduction of water levels, influence significant wave heights HS, which decrease on average by 22% compared to non-regulated conditions, but in the shallower areas (for example tidal flats and salt marshes), the predicted decrease is on average 48%. Consequently, the analysis suggests that the Mo.S.E. closures are expected to induce modifications in the wave overtopping, wave loads and lagoon morphodynamics.

Overtopping and stability of a rubble mound breakwater with coreloc armour under oblique cyclonic waves

Abstract: This note presents the physical model tests carried out on the new breakwater in the fishing harbour of Mirbat (Sultanate of Oman), designed for a cyclonic wave Hs = 6.0 m and for a 200 year return period wind wave Hs = 3.2 m. Based on this experience, the behaviour of a rubble mound breakwater subject to wind waves that are much smaller than the design cyclonic wave height is discussed. We shall define the wave climate in this case as "cyclonic†. The initial interlocking (during construction) that does not "grow† during the lifetime as usual and the expected cyclonic wave is likely to produce larger damage than predicted by the design formulae, that on the contrary rely on such interlocking. Under oblique waves, the importance of unit interlocking is even greater due to the sub-horizontal loads and therefore the case of cyclonic wave climates requires a larger safety margin.

Random seas and design of maritime structures

Abstract: Evolution of Design Method Against Random Waves Statistical Properties and Spectral of Sea Waves Transformation and Deformation of Random Sea Waves Design of Breakwaters Design of Coastal Dikes and Seawalls Probabilistic Design of Harbor Facilities Harbor Tranquility and Vessel Mooring Hydraulic Model Tests with Random Waves Theoretical Description of Random Sea Waves Statistical Theory of Irregular Waves Techniques of Random Wave Analysis 2D Computation of Wave Transformation with Random Breaking and Nearshore Currents Statistical Analysis of Extreme Waves Prediction and Control of Beach Deformation Processes.

Physics-based Bathymetry and Water Quality Retrieval Using PlanetScope Imagery: Impacts of 2020 COVID-19 Lockdown and 2019 Extreme Flood in the Venice Lagoon

Abstract: The recent PlanetScope constellation (130+ satellites currently in orbit) has shifted the high spatial resolution imaging into a new era by capturing the Earth’s landmass including inland waters on a daily basis. However, studies on the aquatic-oriented applications of PlanetScope imagery are very sparse, and extensive research is still required to unlock the potentials of this new source of data. As a first fully physics-based investigation, we aim to assess the feasibility of retrieving bathymetric and water quality information from the PlanetScope imagery. The analyses are performed based on Water Color Simulator (WASI) processor in the context of a multitemporal analysis. The WASI-based radiative transfer inversion is adapted to process the PlanetScope imagery dealing with the low spectral resolution and atmospheric artifacts. The bathymetry and total suspended matter (TSM) are mapped in the relatively complex environment of Venice lagoon during two benchmark events: The coronavirus disease 2019 (COVID-19) lockdown and an extreme flood occurred in November 2019. The retrievals of TSM imply a remarkable reduction of the turbidity during the lockdown, due to the COVID-19 pandemic and capture the high values of TSM during the flood condition. The results suggest that sizable atmospheric and sun-glint artifacts should be mitigated through the physics-based inversion using the surface reflectance products of PlanetScope imagery. The physics-based inversion demonstrated high potentials in retrieving both bathymetry and TSM using the PlanetScope imagery.

The first operations of Mo.S.E. system to prevent the flooding of Venice: Insights on the hydrodynamics of a regulated lagoon

Abstract: In October 2020, for the first time in its thousand-year-old history, the Venice Lagoon has been temporarily closed. The first operations of the Mo.S.E. system, a set of artificial barriers built to isolate the lagoon from the sea in case of high tides, prevented Venice and the other lagoonal settlements from flooding. Beyond its historical value, the closure of the lagoon inlets has led to unprecedented scenarios from a hydrodynamic standpoint. With the Mo.S.E. system operational, significant high tides can no longer be recorded within the lagoon and the undisturbed tide propagation can only be estimated through hydrodynamic modelling. When the inlets are closed and the effect of tide propagation nullified, the action of wind on cross-lagoon setup is enhanced and becomes more clearly recognizable, allowing for a robust calibration of the wind drag coefficient also for low to moderate wind speed. Furthermore, the data collected during the first closures of the Mo.S.E. gates allowed evaluating the real intra-gate infiltration entering the lagoon through the closed gates, and suggested that the gate operation produces some seaward disturbance as well.