Michalis K. Chondros

• Doctor of Engineering
• Assistant Professor at National Technical University of Athens

Coastal flooding is one of the most threatening and detrimental natural disasters affecting coastal areas (Tsoukala et al., 2016, Chondros et al., 2021a), mainly caused by Sea Level Rise (SLR) due to astronomical tide and storm surge, along with the concurrent wave action. The risk increases further in coastal areas with presence of river or stream...

Port and coastal rubble mound structures are constru- cted to minimize the effects of wave action on beaches and harbors. Their structural degradation and, conse- quently, their damage are usually linked to the instability of the armor layer, expressed as rocking, units’ displace- ments, blanket sliding, or settlement (Campos et al. 2020a). Within...

Boussinesq-type wave models (e.g. Shi et al., 2012) have been traditionally employed to simulate wave agitation in port basins, however they are often associated with significant computational burden. An alluring alternative, with respect to the accuracy and efficiency, concerns models based on the time-depended hyperbolic mild slope wave equation,...

The Coastal Resilience Agent-Based Model (CRes-ABM) is introduced, which was created to evaluate the resilience of coastal areas to the effects of climate change, with a particular emphasis on sea-level rise and extreme weather events. The aim is to provide information for developing policies and making decisions about boosting coastal resilience....

Coastal flooding poses a significant threat to coastal communities, adversely affecting both safety and economic stability. This threat is exacerbated by factors such as sea level rise, rapid urbanization, and inadequate coastal infrastructure, as noted in recent climate change reports. Early warning systems (EWSs) have proven to be effective tools...

Numerical modeling of wave transformation, hydrodynamics, and morphodynamics in coastal regions holds paramount significance for combating coastal erosion by evaluating and optimizing various coastal protection structures. This study aims to present an integration of numerical models to accurately simulate the coastal processes with the presence of...

Ensuring sea surface tranquility within port basins is of paramount importance for safe and efficient port operations and vessels’ accommodation. The present study aims to introduce a robust numerical model based on mild-slope equations, capable of accurately simulating wave disturbance and resonance in ports. The model is further enhanced by the i...

This paper presents a recently developed Operational Forecast Platform (OFP) for prevailing sea conditions at very important ports worldwide (Accu-Waves). The OFP produces reliable high-resolution predictions of wave characteristics in and around ocean ports. Its goal is to support safer navigation, predict possible port downtime, assist vessel app...

Coastal areas are dynamic multidimensional systems challenged by the complex interactions between natural, environmental, and human-induced pressures, as well as the ever-changing climate. A comprehensive evaluation of their spatial and temporal features enables the development of effective practices required to apply integrated coastal zone manage...

In this paper, a simple approach to determine representative offshore wave characteristics for estimating the annually averaged sedimentation and erosion trends in sandy coastal areas is presented. Given the offshore wave climate, the proposed approach breaks down the climate into fixed 22.5-degree bins and based on the sediment transport potential...

Process-based models have been employed extensively in the last decades for the prediction of coastal bed evolution in the medium term (1–5 years), under the combined action of waves and currents, due to their ability to resolve the dominant coastal processes. Despite their widespread application, they are associated with high demand for computatio...

This paper presents a new Operational Forecast Platform (OFP) for prevailing sea conditions at very important ports worldwide (project Accu-Waves; http://accuwaves.eu/). The OFP produces reliable, high-resolution, predictions of wave characteristics in and around harboured coastal areas. Its goals are to support safer navigation, assist vessel appr...

Integrated Coastal Zone Management (ICZM) policies require a comprehensive evaluation of the complex coastal spatial and temporal characteristics. Stresses induced by natural hazards, human forces and the ever-changing climate are inherently linked with the coastal vulnerability concept that is elaborated through the employment of multi-faceted ICZ...

Process-based models have been employed extensively in the last decades for the prediction of coastal bed evolution in the medium term (1-5 years), under the combined action of waves and currents, due to their ability to resolve the dominant coastal processes. Despite their widespread application, they are associated with a high demand in computati...

The simulation of wave propagation and penetration inside ports and coastal areas is of paramount importance to engineers and scientists desiring to obtain an accurate representation of the wave field. However, this is often a rather daunting task due to the complexity of the processes that need to be resolved, as well as the demanding levels of re...

Κλιματική αλλαγή: Μεθοδολογία έγκαιρης πρόβλεψης και προειδοποίησης παράκτιων πλημμυρών.

An integrated methodological approach to the development of a coastal flood early-warning system is presented in this paper to improve societal preparedness for coastal flood events. The approach consists of two frameworks, namely the Hindcast Framework and the Forecast Framework. The aim of the former is to implement a suite of high-credibility nu...

The present paper provides an integrated framework for modelling of coastal inundation, aiming to help coastal communities understand their risks and consequently to prevent the adverse effects to society. The proposed framework involves the implementation and coupling of a suite of sea state hindcast data, numerical wave and hydrodynamic models an...

Forecast of wave agitation inside port basins and consequent downtime of berth positions are of utmost importance to make a port "smarter" by efficiently managing its infrastructure. Within Accu-Waves project (http://accuwaves.eu), a decision-making tool is being developed to provide forecast data on prevailing sea states in the vicinity of port en...

Η παρούσα Τεχνική Έκθεση αποτελεί το παραδοτέο Π3.5, το οποίο περιγράφει αναλυτικά τα ακόλουθα σημεία: • Σύντομη περιγραφή των μοντέλων προσομοίωσης o Υδροδυναμικό Μοντέλο Η (HiReSS) o Κυματικό Μοντέλο Α (TOMAWAC) o Κυματικό Μοντέλο Β (WAVE-L) • Περιγραφή της Μεθοδολογίας Αξιολόγησης o Παράθεση της μεθοδολογικής προσέγγισης o Τυπική διάταξη του Δελ...

Η παρούσα Τεχνική Έκθεση αποτελεί το παραδοτέο Π4.1, το οποίο περιλαμβάνει και περιγράφει αναλυτικά τα ακόλουθα σημεία: • Τεχνικές περιγραφές: o Αρχιτεκτονική Συστήματος - Διάγραμμα Ροής ▪ Επιμέρους υποσυστήματα o Τρόποι Επικοινωνίας Μοντέλων ▪ Διάγραμμα επικοινωνίας ▪ Εκτέλεση μοντέλων o Διαδικασίες εκτέλεσης ▪ Παράλληλη εκτέλεση εργασιών ▪ Κύκλοι...

This paper presents a novel initiative for reliable high-resolution forecasts on prevailing sea states at 50 important ports worldwide (Accu-Waves; http://accuwaves.eu/). Its goal is to support safe navigation, unhampered vessel approaching to busy harbored areas, and secure ship maneuvering in ports. Accu-Waves 1 is based on integrated, high-resol...

The ability to reliably forecast sea states (most importantly sea level, wind, and wave conditions) within or close to the entrance of ports is a critical tool for all involved stakeholders. In this paper, we present our work on a prototype decision support system capable of providing accurate sea state forecasts based on three high-resolution hydr...

The long-term prediction of morphological bed evolution has been of interest to engineers and scientists for many decades. Usually, process-based models are employed to simulate bed-level changes in the scale of years to decades. To compensate for the major computational effort required by these models, various acceleration techniques have been dev...

In this paper we present recent evolvements of three robust numerical models for the simulation of the evolution of wave fields and hydrodynamic circulation in gulfs and coastal areas with large harbours and significant urban port facilities. The models are integrated into a single software suite for the development of a decision support tool to pr...

The present paper aims to incorporate nonlinear amplitude dispersion effects in parabolic and hyperbolic approximation models. First, an explicit and analytical method for considering nonlinearities in parabolic approximation models is investigated. This method follows the concept of calculating spatially and temporally varying wave phase celeritie...

Η παρούσα Τεχνική Έκθεση αποτελεί το παραδοτέο Π2.5, το οποίο περιγράφει αναλυτικά τα ακό-λουθα σημεία: • Τις διενεργηθείσες από την ομάδα έργου μετρήσεις πεδίου • Τις παραμέτρους μέτρησης – παρατήρησης • Τη διενέργεια πλόων και τις σχετικές διοικητικές ενέργειες • Τον εξοπλισμό και τα όργανα μέτρησης: Κυματογράφος – σταθμηγράφος τύπου SBE26 και Aq...

Η παρούσα Τεχνική Έκθεση αποτελεί το παραδοτέο Π2.6, το οποίο περιγράφει αναλυτικά τα ακόλουθα σημεία: • Στοιχεία κωδίκων μοντέλων προσομοίωσης Α, Β, Η • Δεδομένα εισόδου – εξόδου μοντέλων προσομοίωσης Α, Β, Η • Στοιχεία ρύθμισης κώδικα μοντέλων προσομοίωσης Α, Β, Η • Υπολογιστικά πεδία εφαρμογής μοντέλων προσομοίωσης Α, Β, Η • Ειδικές παραμετροποι...

Spectral wave models have experienced constant development and vast improvements over the past decades. They are constantly being extended and refined in order to cover the complex wave transformation processes that take place in the coastal zone. Nevertheless, wave transmission due to overtopping has not been treated similarly yet. In this paper,...

Η παρούσα Τεχνική Έκθεση αποτελεί το παραδοτέο Π1.3, το οποίο περιγράφει αναλυτικά τα ακόλουθα σημεία: Περιγραφή και αλυσίδα εφαρμογής μοντέλων Δεδομένα εισαγωγής στα μοντέλα Μετασχηματισμός και προσαρμογή των ατμοσφαιρικών και θαλασσίων παραμέτρων Καθορισμός οριακών και αρχικών συνθηκών Επιλογή λιμένων και καθορισμός βυθομετρικών και γεωμετρικών χ...

Along with the unquestionable temperature rise, ocean thermal expansion and glacier melting lead the average sea level to rise at an ever-increasing rate. This increase, in conjunction with the occurrence of more severe storm surges and higher wave heights during extreme weather events, makes the upgrading of existing harbor infrastructure a necess...

Spectral wave models have experienced constant development and vast improvements over the past decades. They are continuously extended in order to model the complex wave transformation processes that are present in the coastal zone. Nevertheless, wave transmission due to overtopping has not been included properly yet. In the present paper a new met...

The paper presents a decision support tool being developed to provide reliable forecasts on sea states prevailing at selected ports worldwide. The application will support approaching procedures of vessels to ports. It is based on cooperating , hydrodynamic models that derive data from global scale, open sea forecasts. The implementation of the pro...

In this paper we present the evolvement of an integrated numerical model (WAVE-L) for the simulation of wave propagation and transformation in areas around and inside ports and harbors. WAVE-L is a high-resolution phase-resolving wave model based on the hyperbolic mild-slope equations, capable of simulating the transformation of complex wave fields...

In the present paper, an application of composite modeling is presented, for the estimation of wave transmission through flushing culverts. Specifically, Artificial Neural Network (ANN) are training with experimental measurements for the prediction of the transmission coefficient, when these will not be available in the future. Investigating the st...

In the present paper, a package model is derived, based on a joint probability density function and on a Boussinesq-class numerical wave model. The key task was to produce joint probability density estimates of wave-height and wave period in intermediate and shallow waters given the respective information offshore. This is of paramount importance i...

A simple, small array of a few elevation probes is proposed for the estimation of wave directional spreading and the mean wave direction. This technique offers the possibility of such estimations through two comparable methods, that is, the Maximum Likelihood Method and the Maximum Entropy Method. It is noted that the latter method was combined wit...

Coastal floods are regarded as among the most dangerous and harmful of all natural disasters affecting urban areas adjacent to the shorelines. Rapid urbanization combined with climate change and poor governance often results in significant increase of flood risk, especially for coastal communities. Wave overtopping and wave run-up are the key mecha...

Three enhanced versions of two existing nonlinear Boussinesq-type models are herein derived. These models, along with two other similar solvers, were investigated with respect to their nonlinear and dispersive characteristics. In particular, this study comprises Fourier analysis at first-order, second-order, and third-order harmonics; an investigat...

In the present paper, an application of composite modeling is presented, for the estimation of wave transmission through flushing culverts. Specifically, experimental measurements are used and an Artificial Neural Network (ANN) is structured for the prediction of the transmission coefficient. Measurements were obtained from physical model tests tha...

Coastal communities are increasingly at risk from coastal hazards such as floods. Extreme hydro-meteorological events related to sea level rise, storm surges, heavy precipitation, shoreline erosion are driven by climate variability and increase the exposure of people, livelihoods, environmental services, resources and infrastructure to hazard. Floo...

In this study, an investigation was carried out of the ancient harbour of Lechaion (Peloponnese, Greece), regarding its associated coastal sedimentation features. The ancient facility, established around 600 B.C., is positioned on the southeastern edge of the Gulf of Corinth where continuous small steep alluvial fans form the shoreline profile. As...

A modified Boussinesq-type model is derived to account for the propagation of either regular or irregular waves in two horizontal dimensions. An improvement of the dispersion and shoaling characteristics of the model is obtained by optimizing the coefficients of each term in the momentum equation, expanding in this way its applicability in very dee...

For short-term description of sea states, an alternative approach has been proposed by Memos (1994) which combines advantages of existing conventional methods. The essence of that approach is to retain probabilistic information on the associated values of wave height and wave period (H, T), which is of paramount importance in coastal engineering, e...

In the present study an application of composite modelling is presented, for the wave transmission above submerged breakwaters. Specifically, experimental measurements and numerical results from a Boussinesq model in combination with an Artificial Neural Network structured specifically for the forecasting of the transmission coefficient. This model...

In the present study a modified Boussinesq-type model is derived to account for propagation of regular and irregular waves in two horizontal dimensions. An improvement of the linear and nonlinear characteristics of the model is obtained by optimizing the coefficients of each term in the momentum equation, expanding in this way its applicability in...

In the present study a modified Boussinesq-type model is derived to account for propagation of regular and irregular waves in two horizontal dimensions. An improvement of the linear and nonlinear characteristics of the model is obtained by optimizing the coefficients of each term in the momentum equation, expanding in this way its applicability in...

A recent Boussinesq-type model is herein modified to account for breaking waves in shallow water. The model is based on a system of equations in terms of surface elevation and depth-averaged horizontal velocities, in two horizontal dimensions for fully dispersive and weakly nonlinear random waves over any finite water depth. The formulation involve...

In the present work a Boussinesq-type model was modified to account for breaking waves in shallow water. The model is based on a system of equations in terms of the surface elevation and the depth-averaged horizontal velocities, in two horizontal dimensions for fully dispersive and weakly nonlinear irregular waves over any finite water depth, as de...