Hydrodynamic response of artificial lagoons considering tide, wind and tracer — Case study El Gouna, Egypt

Artificial coastal lagoons represent attractive multi-purpose water systems, which offer a great opportunity for tourism and industrial services. El Gouna city, located in Egypt has a system of artificial lagoons connected to the Red Sea and offers a great opportunity for tourism activities. Investigating the hydrodynamics of El Gouna lagoons is an urgent action to mitigate the negative anthropogenic impacts on this attractive environment, ensuring its sustainability. A 2D numerical model using TELEMAC-2D was set up to study the hydrodynamics and tracer transport processes under different weather conditions considering tide, mean wind and maximum wind. Furthermore, the emission of tracer from a nearby desalination plant was simulated to estimate the tracer propagation in the computational domain. Also, the effect of different tracer quantities or different injection times and tracer residence time were computed. This paper presents one of the very few systematic hydrodynamic studies on artificial lagoons. The results showed that the water depths were controlled by tide fluctuations. Besides, the maximum wind increased the flow velocities and the tracer outflow, while the mean wind had minor effects on the water velocities and tracer outflow. The weather conditions affected the tracer propagation direction and its outflowing rate. Moreover, the mean wind with tide case decreased the residence time, when compared to the tidal case. The simulations for the operation of the desalination plant suggested that rapid injection of the tracer may enhance a quicker removal of pollution from the lagoons. The paper’s outcomes are the basis for future studies on the lagoon’s water quality modeling and can support decision-making in the city of El Gouna, concerning water resources management.