Gabriella Petaccia

• Environmental engineering
• Professor (Associate) at University of Pavia

The primary cause of many bridge collapses is related to hydraulic issues, and the Italian technical standards for constructions (NTC 2018) offer limited guidance on the design and verification criteria for bridges, especially concerning river processes. Recognizing this gap, a working group dedicated to “Hydraulic Compatibility of Bridges” (sites....

The paper describes the implementation of internal boundary conditions in the 1D ORSADEM hydraulic model to simulate the effect of a hydraulic in-line structure. The proposed model introduces a simplified representation of the bridge geometry by imposing an equivalent narrowing, computed according to the opening size and characteristics, combined w...

Despite significant advancements being made in recent decades (e [...]

This paper explores the use of the rain-on-grid (or direct rainfall) method for flood risk assessment at a basin scale. The method is particularly useful for rural catchments with small vertical variations and complex interactions with man-made obstacles and structures, which may be oversimplified by traditional hydrologically based estimations. Th...

Laboratory experiments of dam-break flows are extensively used in investigations of geophysical flows involving flood waves, to provide insight into relevant aspects of the physics of the process and collect experimental data for validating numerical models. A dam-break flow is a typical example of a highly unsteady free surface flow with high repr...

This paper aims to present simple regressive equations to estimate the parameters of the three-parameter depth–duration–frequency (DDF) curve (3p-DDF), which accurately expresses, for a preassigned return period, the relationship between the rainfall depth and the rainfall duration over large duration ranges, from below 1 h (i.e., tens of minutes)...

Rapidly changing flows in regulated rivers can significantly impair freshwater biotas. At present, this issue is mostly addressed by hydropeaking research. In contrast, only limited information is available concerning the environmental effects of sharp streamflow variations determined by manmade manipulation other than hydroelectricity generation....

The use of integrated flood models represents an approach of growing interest in the literature, being the hydrological and hydrodynamic flood processes described entirely within the two-dimensional (2D) hydrodynamic unsteady flow equations. Due to its ability in simulating complex spatial-temporal dependence of both the hydrodynamic and hydrologic...

Wood transport during flood events can increase inundation risk and should be included in numerical models to estimate the associated residual risk. This paper presents the application of a fully Eulerian model that considers floating wood as a passive superficial pollutant through the adaptation of the advection–diffusion equation. A set of experi...

This is the reply to the comments by AlQasimi and Mahdi (2022) on the classification attributed to the Lake Ha! Ha! real-field test case by Aureli et al. (2021) in their review of historical dam-break events useful for the validation of dam-break numerical models. While admitting that this test case is affected by the data shortcomings reported by...

Dam break inundation mapping is essential for risk management and mitigation, emergency action planning, and potential consequences assessment. To quantify flood hazard associated with dam failures, flooding variables must be predicted by efficient and robust numerical models capable to effectively cope with the computational difficulties posed by...

The drag and side force coefficients of a half-submerged cylinder in a free-surface flow were calculated through numerical simulations, with the aim of supporting the numerical modelling of log transport in rivers. The variability of these coefficients with the yaw angle with respect to the flow direction and with the ratio between the flow depth a...

The drag and side force coefficients of a half-submerged cylinder in a free-surface flow were calculated through numerical simulations, with the aim of supporting the numerical modelling of log transport in rivers. The variability of these coefficients with the yaw angle with respect to the flow direction and with the ratio between the flow depth a...

An advection-diffusion model is proposed to simulate large wood transport during high flows. The mathematical model is derived from the wood mass balance, taking into consideration both the wood mass concentration and the log orientation, which affects log transport and, most importantly, wood accumulation. Focusing on wood mass transport, the adve...

The Hydrologic Engineering Centre-River Analysis System (HEC-RAS), developed by the US Army Corps of Engineers, is one of the most known, analyzed and used model for flood mapping both in the scientific literature and in practice. In the recently released version (release 5.0.7), the HEC-RAS model has been enriched with novel modules, performing fu...

Numerical models trying to faithfully represent the movement of floating bodies transport in open-channel flow require experimental data for validation. In order to provide an adequate dataset, flume experiments were carried out to analyse the transport of singular and grouped rigid bodies floating on the water surface. Both cylindrical and spheric...

Wood transport during high flow events is here treated as an advective–diffusive phenomenon. A theoretical definition of the governing equation is first provided, highlighting the dependence of floating wood diffusion on the adoption of adequate diffusion coefficients. To estimate these coefficients, an experimental investigation on large wood debr...

The Eulerian–Lagrangian model ORSA2D_WT is employed for the simulation of uncongested wood transport, with reference to a field experiment that studied the motion of regular and unbranched cylindrical wooden samples. The model calculates the entrainment, transport and deposition of large wood elements by computing the hydrodynamic forces exerted by...

The Bric Zerbino and Sella Zerbino barrages dammed two branches of the Orba Valley in Italy to create the Ortiglieto reservoir and supply the Molare hydropower plant. The secondary dam, the Sella Zerbino, was erected over a fault, whose geotechnical characteristics were deemed extremely poor. On August 13, 1935, a very intense and localized storm p...

This paper aims to analyze the flood hazard in the city of Monza, which periodically suffers from overflows from both the river Lambro and the urban drainage system during wet weather conditions. A unified Urban Flash Flood Model of Monza is therefore developed to capture both sources of hazard. The model is first validated by comparing the results...

The increasing availability of high-resolution terrain data fostered the development of two-dimensional hydrodynamic-based surface runoff models at basin scale, for flood hazard assessment and mapping purposes. The generation of the computational domain is one of the most important preliminary steps for practical applications of this kind of modeli...

The hydrodynamic response of a cylinder in an open-channel flow is experimentally investigated by considering the effects of horizontal orientation and submergence, the latter ranging from fully submerged to half-submerged cases. Drag and side coefficients are measured with a specific hydrodynamic balance which allows the planar rotation and the va...

A computational Eulerian-Lagrangian model (ORSA2D_WT) is used for modelling the movement of floating rigid bodies on the water surface. The two-dimensional transport is computed with a dynamic approach, modifying existing formulations for the transport of bodies within fluid flows for the case of floating bodies, by adopting suitable added mass, dr...

The paper discusses a model which predicts the trajectory of floating rigid bodies and may be applied to compute the motion of woody “debris” mobilized during floods. The model couples a Discrete Element (DE) Lagrangian approach for the calculation of motion of rigid bodies with the Eulerian solution of the shallow water equations (SWE), in order t...

The paper describes the calibration of a numerical model to simulate the 2D motion of floating rigid bodies. The proposed model follows a one-way coupling Eulerian-Lagrangian approach, in which the solution of the Shallow Water Equations (SWE) is combined with the Discrete Element Method (DEM) to compute the displacement of rigid bodies. Floating b...

This paper presents two 2D dam break parallelized models based on shallow water equations (SWE) written in conservative form. The models were implemented exploiting multicore PC systems and graphics processor unit (GPU) architectures under the OpenMP and the NVIDIA™’s compute unified device architecture (CUDA) frameworks. The mathematical model is...

When a severe flood wave completely filled the Ortiglieto reservoir on August 13, 1935, the 14m high “Sella Zerbino” secondary dam failed catastrophically causing >100 casualties. Both of the dams, Sella Zerbino-Zerbino Saddle and Bric Zerbino-Zerbino Peak (Fig. 1) were overtopped but only the Sella Zerbino failed whereas the main barrage did not s...

The numerical modelling of circulations in shallow lakes is a relevant tool for all environmental applications in which flow advection processes are of interest, e.g. for studies on nutrients, microorganisms, pollutants and sediment dynamics. While 3D models are needed to properly describe the flow fields of basins with the main circulations in the...

Coupled 1D-2D numerical strategies are presented in this work for their application to fast computation of large rivers flooding. Both 1D and 2D models are built using explicit upwind finite volume schemes, able to deal with wetting-drying fronts. The topography representation is described via cross sections for the 1D model and with quadrilateral/tr...

Coupled 1D-2D numerical strategies are presented in this work for their application to fast computation of large rivers flooding. Both 1D and 2D models are built using explicit upwind finite volume schemes, able to deal with wetting-drying fronts. The topography representation is described via cross sections for the 1D model and with quadrilateral/...

Nowadays, the use of 2-D fully dynamic models represents the most reliable approach for flood inundation and flood hazard studies, especially in complex applications. However, 1-D modeling is still a widely used approach due to the reduced computational time and cost. The introduction of LIDAR technique has stimulated a more detailed topographic de...

In this paper the impact induced by bridges on the river flow is studied applying 1-D and 2-D unsteady flow models. Both the models are based on the Shallow Water Equations written in conservative form and solved with first order upwind schemes. In particular, the effect of bridges on the flow behavior simulated by the models is discussed from a pr...

On 13th August 1935, an heavy storm settled over the Ortiglieto reservoir in the Piedmont region of Northern Italy. The reservoir was created by two dams: the main one, Bric Zerbino, having spilling facilities; the secondary dam, Sella Zerbino, with no spillway function. During the 1935 event, Bric Zerbino spillways were unable to release the inflo...

This paper deals with the application of flood propagation models in rivers with skewed bridge crossings. In such situations, the application of 1-D models is not trivial because of the uncertainty related to the narrowing induced by bridge piers within the cross-sections. In order to study this problem, this paper investigates 1-D and 2-D state-of...

In 1925 two dams were constructed across the Orba River to store water in Ortiglieto reservoir. The 13th of August 1935 the flood spillways of the main dam - Bric Zerbino - were unable to discharge the flood and both dams were overtopped. The main dam was not damaged while secondary dam - Sella Zerbino - collapsed. This paper describes in detail th...

This paper describes the ORSADEM software, which solves one-dimensional (1-D) shallow water equations written in conservative form by numerical schemes suitable for the modelling of shocks and discontinuities generated by a dam break. Unlike the majority of commercial software, ORSADEM automatically defines the model cross-sections based on the ter...

La memoria inizialmente si sofferma su un aspetto di pertinenza idraulica nell'ambito della revisione delle NTC 2008 attualmente in corso presso il Consiglio Superiore dei Lavori Pubblici. Si sta dibattendo infatti sul come calcolare le luci libere nel caso di ponti inclinati rispetto all'asse della corrente. Non esistendo sull'argomento uno standa...

The EU flood risk Directive (Directive 2007/60/EC) prescribes risk assessment and mapping to develop flood risk management plans. Flood hazard mapping may be carried out with mathematical models able to determine flood-prone areas once realistic conditions (in terms of discharge or water levels) are imposed at the boundaries of the case study. The...

Most of the recent developments concerning efficient numerical schemes to solve the shallow-water equations in view of real world flood modelling purposes concern the two-dimensional form of the equations or the one-dimensional form written for rectangular, unit-width channels. Extension of these efficient schemes to the one-dimensional cross-secti...

Risk analysis has become a top priority for authorities and stakeholders in many European countries, with the aim of reducing flooding risk, considering the population's needs and improving risk awareness. Within this context, two methodological pieces have been developed in the period 2009-2011 within the SUFRI project (Sustainable Strategies of U...

Simplified and detailed two-dimensional modeling approaches to transient flows in urban areas, based on finite-volume solution of the shallow water equations, are compared. Through the example of a dam-break flow in a simplified urban district for which accurate laboratory data exist, various methods are compared: (1) the solution of the two-dimens...