Re-originate Burullus coastal lake's ecosystem using salinity dynamics as a management tool

• A 2D-depth averaged transport model based on MACS algorithm has been developed.
• The Model gave a good agreement between measured and predicted results.
• Five scenarios were studied to improve Burullus Lake salinization process.
• Fresh water flow is needed to avoid lake hyper salinity.
• New discharge routing showed significant improvement in lake salinity values.

Burullus lagoon is a brackish water coastal lake on the Mediterranean Sea, Egypt. Lake ecosystem has deteriorated since Aswan High Dam Construction, 1965. Lake salinity has suffered from significant decrease due to excess unregulated drainage water effluent into the lake, which affected the lake flora and fauna. This study presents a two-dimensional depth-averaged mass transport model with the finite volume method (FVM) in discretization to simulate salinity distribution under actions of wind and tidal current for Burullus shallow coastal lake. This model is based on MAC on unstructured collocated grid for shallow water equations (MACS algorithm) with the distributed memory system to increase the computational efficiency on the basis of domain decomposition method. This method is implemented by MPI (message-passing interface), which allows us to (significantly) reduce the elapsed time of computation. It has a potential for long-term simulation for coastal process. Good agreement between analytical, experimental, and field measured data and predicted salinity has been achieved during model verification. Different scenarios have been studied to understand the lake salinity dynamics and circulations, and to develop the most adequate solution for environmental management. These scenarios revealed the importance of fresh drainage water release into the lake and the possibility of its use as an artificial flood similar to pre-Aswan High Dam construction flood under a well-monitored control system.