Computational Fluid Dynamics modeling has been applied to examine the hydrodynamic behavior of water treatment sedimentation tanks at Baghdad Water Works, operated by Alkurech Water in Baghdad in Iraq. The existing tanks perform poorly at current flows and flow is unevenly split among online tanks, Therefore, CFD was used to investigate velocity profiles at current and projected loadings for the existing basins. Results from the CFD analysis were used to develop retrofit strategies to improve velocity profiles , design and operation of sedimentation tanks in the existing basins. The paper shows how CFD can be helpful in order to improve the design of existing water treatment plants and the process efficiency. In this scope, CFD enables designs more reliable and cost effective water treatment process which remain basic environmental policy issues.Computational Fluid Dynamics modeling has been applied to examine the hydrodynamic behavior of water treatment sedimentation tanks at Baghdad Water Works, operated by Alkurech Water in Baghdad in Iraq. The existing tanks perform poorly at current flows and flow is unevenly split among online tanks, Therefore, CFD was used to investigate velocity profiles at current and projected loadings for the existing basins. Results from the CFD analysis were used to develop retrofit strategies to improve velocity profiles , design and operation of sedimentation tanks in the existing basins. The paper shows how CFD can be helpful in order to improve the design of existing water treatment plants and the process efficiency. In this scope, CFD enables designs more reliable and cost effective water treatment process which remain basic environmental policy issues.