NIKOS KOTSOVINOS

The scope of the present study was to predict the shoreline change in the wider area of the Port of Alexandroupolis, forty years from today. In order to achieve our goal, we used the commercial software package CEDAS (Coastal Engineering Design and Analysis System) and in particular, the numerical models of NEMOS (NEMOS is a part of CEDAS software). The most important input data (referring to the study area) for the numerical models of NEMOS were: bathymetric data, the port of Alexandroupolis, relative wave timeseries in deep water conditions which are application results of the model WAM performed for the Aegean Sea by H.C.M.R., and past and contemporary shorelines of the area which were produced by processing satellite images and field measurements. The extracted shorelines were used as reference shorelines in the sensitivity tests and the calibration of NEMOS models. The simulation results, show the parts of the study area which are under erosion and those which are under accretion.

We consider the problem of the vertically upwards disposal of heavy brine sewage from a two-dimensional diffuser in a lighter, homogeneous, motionless and shallow ambient sea. The rejected high salinity water of seawater desalination plants for urban and agricultural uses is such a case of a two dimensional fountain. The disposal of brine sewage produces a negative buoyant jet due to its initial momentum, which impinges on the free surface, spreads laterally on it and then sinks downwards, because of the negative buoyancy. Laboratory experiments and dimensional considerations are used in this paper in order to investigate the spreading behavior (width) of the vertical fountain which impinges on the free surface of the shallow ambient fluid. The experimental results have been used to derive an equation relating the width at the free surface with the initial parameters of the flow. In addition, the experimentally measured dilution of the heavier brine sewage on the recipient’s surface is compared with the dilution which was calculated by a numerical simulation of a well-known commercial software package, CORJET (a CORMIX sub model).

ABSTRACT The basic objective of this study is the understanding of the hydrology and hydraulic characteristics of Lake Vistonis, a very shallow lake in Northern Greece, connected to the Aegean Sea through an irregular shallow channel. In this paper we estimate the pollutant residence time and the discharge of lake to the Aegean Sea as a function of lake elevation. Also we determine the seasonal variations of salinity of the lake.