Papers by Francesco Pasanisi
Journal of Applied Engineering Sciences
Some of the first outcomes of a project aiming at mapping the renewable energy potential in Lesot... more Some of the first outcomes of a project aiming at mapping the renewable energy potential in Lesotho are hereby presented. In particular, the present paper deals with the task of the project devoted to produce a digital hydrographic map of Lesotho and an associated geographic database. Different geographical, meteorological and hydrological data were collected in the first steps of the project. The hydrographic network was derived in vector format from a digital elevation model of Lesotho using geoprocessing tools in GIS environment. Results were compared with existing cartography and satellite images. Moreover, a methodology proposed in literature for the assessment of the theoretical maximum hydroelectric producibility at watershed level in Italy was applied to one of the main catchment areas of Lesotho. The activities planned to fulfil the objectives of the project are finally outlined.
Sustainability
In this paper the background, activities undertaken, and main outcomes of the cooperation project... more In this paper the background, activities undertaken, and main outcomes of the cooperation project “Renewable Energy Potential Maps for Lesotho” are presented. The project was launched in 2018 in fulfilment of the Paris Agreement by the Italian Ministry for the Environment and the Lesotho Ministry of Energy and Meteorology, with the aim to facilitate the local Government in the future planning and development of renewable energy in the country. A user-oriented WebGIS platform was utilised to share and analyse the outcomes of the project: a hydrological map to recognize potential areas for power generation; a wind atlas to identify specific sites with the most potential for wind energy generation; a solar radiation map, defining the different levels of radiation intensity, useful to localise sites for photovoltaic production. Human capacity building and technology transfer were carried out to strengthen the local expertise and ability to manage and plan renewable energy sources exploi...
Modeling Earth Systems and Environment
Modeling Earth Systems and Environment
Geosciences
In the present work, preliminary results are reported from an ongoing research study aimed at dev... more In the present work, preliminary results are reported from an ongoing research study aimed at developing an improved prediction model to estimate the sediment yield in Italian ungauged river basins. The statistical correlations between a set of hydro-geomorphometric parameters and suspended sediment yield (SSY) data from 30 Italian rivers were investigated. The main question is whether such variables are helpful to explain the behavior of fluvial systems in the sediment delivery process. To this aim, a broad set of variables, simply derived from digital cartographic sources and available data records, was utilized in order to take into account all the possible features and processes having some influence on sediment production and conveyance. A stepwise regression analysis pointed out that, among all possibilities, the catchment elevation range (H r), the density of stream hierarchical anomaly (D a), and the stream channel slope ratio (∆S s) are significantly linked to the SSY. The derived linear regression model equation was proven to be satisfactory (r 2-adjusted = 0.72; F-significance = 5.7 × 10 −8 ; ME = 0.61), however, the percentage standard error (40%) implies that the model is still affected by some uncertainties. These can be justified, on one hand, by the wide variance and, on the other hand, by the quality of the observed SSY data. Reducing these uncertainties will be the effort in the follow-up of the research.
Earth Science Informatics, 2016
ABSTRACT In order to control the discharges into the sea of domestic sewage and industrial wastes... more ABSTRACT In order to control the discharges into the sea of domestic sewage and industrial wastes, and prevent marine pollution, mathematical models can effectively be used to simulate the transport of pollutants in coastal areas. Such models must describe both the coastal zone hydrodynamics and the processes of advection-diffusion of the pollutants. For the finite difference solution of the hydrodynamics and advection-diffusion equations many numerical schemes have been proposed. The purpose of the present work is to compare, as regards the computing time, several classical schemes for the numerical solution of the hydrodynamics and advection-diffusion equations. For each of the examined schemes, it is shown how the time complexity of the algorithm depends on the dimensions of the calculation grid and on the physical variables of the processes to be simulated. The time complexities of the different methods have been compared and discussed, investigating the geometrical and physical conditions for which different schemes show equivalent time complexities.
In order to control the discharges into the sea of domestic sewage and industrial wastes, and pre... more In order to control the discharges into the sea of domestic sewage and industrial wastes, and prevent marine pollution, mathematical models can effectively be used to simulate the transport of pollutants in coastal areas. Such models must describe both the coastal zone hydrodynamics and the processes of advection-diffusion of the pollutants. For the finite difference solution of the hydrodynamics and advection-diffusion equations many numerical schemes have been proposed. The purpose of the present work is to compare, as regards the computing time, several classical schemes for the numerical solution of the hydrodynamics and advection-diffusion equations. For each of the examined schemes, it is shown how the time complexity of the algorithm depends on the dimensions of the calculation grid and on the physical variables of the processes to be simulated. The time complexities of the different methods have been compared and discussed, investigating the geometrical and physical conditio...
The interaction between a wave and a submerged barrier is characterized, beside a global reductio... more The interaction between a wave and a submerged barrier is characterized, beside a global reduction of the transmitted wave in the sheltered area, by a different frequency distribution of wave energy with respect to the incident wave, due to non-linear effects in the shallow water region over the dike. The process has been described, in the past, both theoretically (in absence of wave breaking) and by means of physical model studies (in the case of non-breaking and breaking waves over the structure); results show that, when wave breaking occurs over the breakwater, the wave-structure interaction, beside causing a higher wave energy dissipation, reveal different properties with respect to the case of non-breaking waves. The aim of the present work is the study of several aspects of the interaction between a wave and a submerged barrier and, mainly, the investigation of the wave breaking effects on the process, taking into account the different breaker types. For this purpose, experime...
An experimental study was commissioned to evaluate, at design stage, the performance of a beach n... more An experimental study was commissioned to evaluate, at design stage, the performance of a beach nourishment protected by a submerged rubble mound breakwater with gaps in Agropoli (Gulf of Salerno). Experiments were performed in the 3D wave basin at University of Napoli Federico II. Results showed that under extreme wave conditions no significant loss of material is to be expected through the gaps of the structure. Measured post-nourishment coastline retreats due to cross-shore processes were comparable with prediction obtained using mathematical models.
A III level reliability analysis, considering different failure modes, has been applied to an ide... more A III level reliability analysis, considering different failure modes, has been applied to an ideal rubble mound breakwater designed with deterministic criteria, located along the Italian coast, near Formia (Thyrrenian Sea). The examined failure modes are the instability of armour layer, the erosion of toe berm and the interaction between them. On the basis of existing wave data, the statistical distribution of the extreme wave heights has been derived, in the hypothesis that it is described by a Weibull function. The reliability analysis has been performed applying Monte Carlo simulations. Random values of wave height have been generated and combined into the limit state equations describing the failure modes of the breakwater. The probability of failure has been estimated for different times and for each examined failure mode.
In the present paper a numerical model for the coastal morphodynamics simulation near a river mou... more In the present paper a numerical model for the coastal morphodynamics simulation near a river mouth is presented. The hydrodynamic phenomena are described first, by using a 2DH numerical model; in the equation of motion the radiation stress components are present, as wave induced time-averaged forces; the wave refraction in the presence of a current is studied by an appropriate mathematical model. The 2DH equations are solved numerically by using a semi-implicit finite difference method, in which an Eulerian-Lagrangian approach is used to discretize the substantial derivatives of the velocity components; the discretized system is solved by a Two-Levels Alternated Directions method. Once the velocity field in front of the river is known, the effects on the sediments can be analyzed. The solid transport rate, only for the bed transport, is evaluated by means of Peter-Meyer and Muller formula. In order to determine the bed morphology evolution, a balance equation for the sediments in e...
study deals with the sedimentation in two reservoirs in Sicily (southern Italy), in order to asse... more study deals with the sedimentation in two reservoirs in Sicily (southern Italy), in order to assess the role played by the different geologic, climatic, geomorphologic and land use characteristics of the upstream watersheds in determining the sediment production and transport capacity. Besides the assessment of the reservoirs efficiency, the measure of sedimentation volume allows to evaluate the net erosion in the upstream basins. Thus, the results can be used for testing and calibrating different models for river sediment yield and for soil erosion estimation. The calibration of such methods plays a key role particularly in areas threatened by desertification, as southern Italy. The examined reservoirs (Comunelli and S. Rosalia) show very different behaviours. The Comunelli reservoir suffers from a very severe reduction of storage capacity, whilst in the S. Rosalia reservoir a very low siltation can be measured. The comparison between the two upstream watersheds showed that the geolithological factor is prominent in determining the different measured sedimentation rates. In addition, the distribution of slope-steepness classes with respect to the reservoir location also appears as a significant factor, more than the average watershed slope value, which is quite similar in the two watersheds. Climatic and land use characteristics are not making the difference, as similar conditions can be described in both cases. This study puts into evidence the need to deal with more efficient theoretical models, in order to predict both soil erosion and reservoir siltation, mainly in the perspective of long-term climatic changes.
Geosciences
Sediment connectivity is a major topic in recent research because of its relevance in the charact... more Sediment connectivity is a major topic in recent research because of its relevance in the characterization of the morphology of river systems and assessing of sediment transport and deposition. Currently, the connectivity indices found in the literature are generally dimensionless and need to be coupled with quantitative soil-loss data for land management and design purposes. In the present work, a simple methodology is proposed to assess two different indices, namely, the simplified connectivity index (SCI) and the specific sediment potential (SSP), based on geomorphometric tools that are commonly available in commercial and open-source geographic information system (GIS) platforms. The proposed metrics allows us to easily assess both the SCI and the SSP as functions of the estimated soil erosion per unit area of the catchment and of the inverse distance of each unit area from the river outlet, this distance being measured along the network path. The proposed indices have been devised to express, respectively, the potential sediment transfer ability and the sediment mass potentially available at a given section of the drainage network. In addition to other parameters used to describe the catchment characteristics potentially affecting the river sediment delivery capacity, the SCI and SSP indices can help to refine theoretical models in order to assess the sediment yield (SY) in ungauged river basins.
Environments, 2016
The paper reports a field investigation on a reach of the lower Zambezi River about 230-240 km do... more The paper reports a field investigation on a reach of the lower Zambezi River about 230-240 km downstream of the Cahora Bassa dam in the Republic of Mozambique. In the framework of a wider research program, bathymetric measures of the riverbed were performed on a 10 km stretch of the river using an echo sounder, a GPS receiver, and an integrated navigation-acquisition system. Field observations and measures revealed a general agreement with macro-features of river morphology reported in early literature, dealing with the morphological response of the river to the construction of large dams, in the second half of the 20th century. Results hereby reported are some of the few examples of direct field measures in the lower Zambezi reported in literature, and could be used by researchers and practitioners either as a knowledge base for further surveys or as input data for validation and calibration of mathematical models and remote sensing observations.
Journal of Hydro-environment Research, 2008
Results of an extensive experimental study on the interaction between waves and submerged barrier... more Results of an extensive experimental study on the interaction between waves and submerged barriers are presented. In particular, the present paper deals with identification of breaking conditions and morphological description of breaker types occurring on a submerged rubble mound breakwater. Barriers with varying geometry and permeability were used for tests. Video data were collected and analyzed and, in case of breaking, different classes and subclasses of breaker types were described and classified, considering: (a) the features of the incipient mechanism of wave rupture, (b) the shape of wave profile at breaking and (c) the evolution of breaker travelling above and leeward of the barrier. The breaker index, i.e. wave height to crest freeboard ratio at incipient breaking was studied as a function of the structure layout and wave parameters; experimental results were found to reasonably agree with Goda and Morinobu (1998) findings and a best-fit expression for scale parameter in Goda breaking formula was derived. A first parameterization of breaker types was then proposed, considering both wave and structure characteristics, described by appropriate non-dimensional numbers.
Experimental tests on interaction between a wave and a submerged rubble-mound breakwater were per... more Experimental tests on interaction between a wave and a submerged rubble-mound breakwater were performed in wave flume at University of Napoli Federico II. Different incident wave conditions were tested, including both non-breaking and breaking waves over the barrier. In cases of breaking, different breaker types at structure were described and classified according to hydraulic-morphological criteria. Experimental results show, according to early literature, that wave breaking induces a saturation in non-linear processes that characterize wave-structure interaction. Effect of saturation on 2 nd order transmitted free waves amplitude was investigated, and a best-fit formula was derived. A simple approximate method for wave profile prediction leeward of the barrier is finally proposed.
In the framework of a wider research project, aimed at developing an high performance computing i... more In the framework of a wider research project, aimed at developing an high performance computing infrastructures in Southern Italy, the SISI project aims at developing customized GIS tools for vulnerable site selection in Italian territory. Vulnerable sites will be defined based on co-presence of different dangerous/vulnerable geographic features in given areas. Morphological and topological criteria will possibly be included in territorial diagnostics.
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Papers by Francesco Pasanisi