The Al-Salam Pump Station will be constructed in the framework of Jeddah Storm water Masterplan (JSWM) in Saudi Arabia. The station discharges the incoming flow from the Al-Salam storm tunnel to the Red Sea. Its structure includes a circular deep wet well (22m diameter and 20m depth below the ground) equipped with six pumps, one weir feed channel (6 m length, 10m width) equipped with four pumps, two pumping channels and two gravity discharge channels. Simulations have been carried out using CFD numerical modelling (Flow-3D) to verify the hydrodynamic performance of such a structure. The hydraulic analysis focuses on aspects such as flow velocity fields and distribution, water elevations, shear stresses and vorticities. The numerical simulations allowed to verify the hydraulic operation and design/performance criteria. These criteria include the allowable freeboard, minimum shear stress to transport sand particles and organic materials, the critical submergence of pumps for different hydrological scenarios, and finally the pre-swirl angle of the pumps. Simulation results show uniform velocity distribution in the wet well as well as in the pumping channels and provide plausible information to confirm design criteria fulfilment.