Chiara Favaretto

Bio: Chiara Favaretto is an academic researcher from University of Padua. The author has contributed to research in topics: Coastal flood & Wave flume. The author has an hindex of 5, co-authored 13 publications receiving 88 citations.

Vulnerability Analysis of the Venetian Littoral and Adopted Mitigation Strategy

Abstract: This paper discusses the key aspects of the recent Coastal Plan of the Veneto Region (IT). Its aim is to propose a single mitigation strategy for coastal erosion that is valid for the whole Veneto Region, and possibly elsewhere, as well as a method to assign a priority level to any action. The suggested mitigation action against erosion depends on urbanization level, beach width, as well as cross-shore and long-shore sediment transport. The criterion used to give a priority level to mitigation actions is based on a vulnerability index that takes into account erosive tendency, existing coastal flooding hazards, coast value, environmental relevance, tourist pressure, urbanization level, the presence of production activities, and cultural heritage. A sample case featuring the littoral of Rosolina is also provided and includes a site description, the sediment budget, critical issues and possible mitigation measures.

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.

Coastal Flooding Hazard Due to Overflow Using a Level II Method: Application to the Venetian Littoral

Abstract: In recent years, marine flooding and its impacts have become a question of growing interest, since coastal areas are the most heavily populated and developed land zones in the world. This paper presents a rapid tool for mapping at regional scale the hazard associated with coastal flooding due to overflow. The tool merges a recently developed numerical model that solves a simplified form of the Shallow-Water Equations and is suited for Graphic Processing Unit (GPU) acceleration, with a Level II reliability method that allows producing hazard maps of inland flooding propagation. The procedure was applied to two stretches of the Venetian littoral, i.e., Valle Vecchia and Caorle, located in the northern Adriatic Sea. The application includes the site descriptions and the resulting hazard maps that show the probability of failure in each point of the coast for a given inland inundation level.

Hybrid Structure Combining a Wave Energy Converter and a Floating Breakwater

Abstract: This experimental study investigates on a hybrid structure consisting in an “active” floating breakwater (FB), coupled with a new type of wave energy converter, named ShoWED. The hybrid structure achieves the double purpose of generating electrical energy and of protecting marinas. The specific objective of the tests is to evaluate the performance of the ShoWED when installed in front of a FB and the effects of the wave energy device on the performance of the FB. Physical model tests were carried out at two different scales: 1) in scale 1:20, necessary to evaluate the performance and dynamics of the FB in the absence of the ShoWED. 2) in scale 1:1, in order to evaluate the efficiency of the ShoWED, at different distances from a rear reflective vertical wall, simulating the presence of the FB. A peculiarity of these latter tests is that the real PTO was tested, allowing to measure the produced electrical energy, as a function of the real external electrical impedance. It is concluded that the ShoWED is able to harvest electrical energy if the incident wave height is larger than 0.05 m, a limit possibly given by some friction threshold in the PTO, and if the wave has a period longer than 1.0 s, a limit possibly caused by the finite width of the floater, 70 cm, not negligible compared to the wavelength associated to periods smaller than 1 s. Maximum excursion of the floater are achieved when the floater location takes advantage of the total reflection of the rear wall: for T=2 s, a 26% efficiency was obtained (measured with a “wave to wire” approach), so that a 10 cm wave height produced 7 W in the laboratory. The reflection and transmission characteristics of the hybrid structures were evaluated indirectly, and the benefits compared to a traditional FB should be appreciable especially for long waves.

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.