Gaweesh and Ahmed (2009) Arwadex 2009 1 Modeling of Thermal Power Plant Water Effluents into Coastal Areas - Analogous to Thermal Desalination Plants Ahmed M. Gaweesh 1 and Ahmed S. M. Ahmed 2 1 MSc., Research Associate, Hydraulics Research Institute, Egypt 2 Ph.D., Associate Professor, Hydraulics Research Institute, Egypt ABSTRACT The operation mechanism of desalinated plant (e.g. Multi Stage Flash) produces effluent discharges to coastal areas with hyper-saline and significantly elevated temperatures. This mechanism is more analogous to the operation of power plant cooling systems. Evaluating the impact of the effluent from such plants is one of the issues in concern. Large scale effluents can potentially have a significant impact on the surrounding environment, commonly the coastal marine environment. Power plants using thermal energy in heat production also discharge water with elevated temperatures and salinity. Predicting the behavior of the water discharged from circulating cooling water systems is an integral part of power plant licensing and permitting processes issued by the environment protection authorities. This is attributed to the fact that thermal load is discharged into natural water environment. This paper presents a case study on the Egyptian Mediterranean Coastline of modeling the thermal effluents behavior discharged into coastal environment using the process based Delft3D model. The Mediterranean Sea is a wave-dominant environment. The model’s 2-D mode was applied to compute wave, current and thermal advection diffusion. The extent of thermal plume was computed for different wave conditions. The excess temperature (rise above ambient) potentially affects the efficiency of the power production. The critical wave condition and its duration which produces large excess temperature at the intake structures were determined. INTRODUCTION Desalination plants based on thermally driven distillation processes relatively produce the highest quantity of distilled water among desalination processes. The operation mechanism of thermal desalination plants (e.g. Multi Stage Flash) produces effluents discharged to coastal areas with hyper-saline and significantly elevated temperatures. This mechanism is similar to the operation of power plant cooling systems. Evaluating the impact of the effluent from such plants is one of the issues in concern. Large scale effluents can potentially have a significant impact on the surrounding environment, commonly the coastal marine environment (Davidson and Nokes, 2007). Power plants using thermal energy in generating electrical energy also discharge water with elevated temperatures and salinity. Predicting the behavior of the water discharged from circulating cooling water systems is an integral part of a power plant