1. Ph.D. Candidate, School of Civil Engineering, National Technical Univ. of Athens, Zografos 15780, Greece (corresponding author).
2. Professor Emeritus, School of Civil Engineering, National Technical Univ. of Athens, Zografos 15780, Greece.
3. DHI Water and Environment, Coastal and Estuarine Dynamics, Agern Allé 5, 2970 Hørsholm, Denmark.