Water Circulation Model of Sharjah’s Coastal Lagoons: A Case Study of Al Khan Lagoon Using Delft 3D Modeling

Rapid urbanization and global warming, associated to rising sea levels, are intensifying coastal hazards in regions like the Arabian Gulf. In Sharjah, three lagoons Al Khalid, Al Mamzar, and Al Khan play a crucial role in the region's coastal socio-economic environment. Intensive human activities are negatively impacting local hydrodynamics, water exchange efficiency, and water quality in these lagoons. This paper investigates water circulation in Al Khan Lagoon by applying a hydrodynamic model using Delft 3-D flexible mesh. The model was calibrated and validated with available data on current speed, direction, and tidal levels. Scenarios with various sea level rises (SLR) projected over the next century were also explored. Model results for a 1–m SLR indicate a 35% increase in tidal range, with current velocities rising from 0.31 to 0.43 m/s, enhancing water circulation and reducing residence time from 27 to 14 days. Although inner lagoon areas experience longer residence times, the system overall disperses materials more effectively, potentially improving water quality. It is concluded that SLR will likely enhance water exchange dynamics in Sharjah's lagoons.