PARABOLIC MODELS FOR THE STUDY OF EQUILIBRIUM IN MAN-MADE AND NATURAL BAYS

Gonzales and Medina (2000) used a simple model to analyze the static equilibrium of bays, based on these fundamental hypotheses: the static equilibrium can be obtained by using Hsu and Evans (1989) parabolic model but the orientation of the wave-front at refraction point is that of the mean wave-energy flow in the given area; the down-coast limit can be fixed using the connection proposed by the angle alpha min. Gonzalez(1995)proposed an analytical expression for this angle, valid in case of diffraction with weak refraction, finding that the value of the angle is a function of the distance of the beach to the wave length. The model proposed by Gonzalez and Medina can be useful in resolving a great number of engineering problems involving both fully developed and undeveloped bays. it is possible to examine the stability of a given bay or to draw up a plan for a new bay. In the paper, the validity of Gonzalez and Medina model has been proved in time by comparing it with the present equilibrium profile of a shore situted on the Tyrrenian side of Calabria, to the South of the province of Vibo Valentia. The beach stretches at firts in a NW-SE direction, between the promontories of Capo Vaticano to the west and of Torre Santa Maria to the east and then continues in a series of curves towards the Scogli della Galea. The beach profile corresponds exactly to that foreseen by the Gonzalez and Medina model.