This thesis analyses the combined mechanical and hydraulic effects of vegetation on reinforced-soil embankment dams. While vegetation is widely recognized for influencing slope stability through root reinforcement and hydrological processes such as evapotranspiration, its role in reinforced embankment dams particularly under varying reservoir levels, seepage conditions, and wave-induced loading remains insufficiently understood. The research adopts an integrated approach combining literature review and numerical modelling. Using Slide2, a limit-equilibrium slope-stability software, a series of parametric analyses was conducted to evaluate the factor of safety and probability of failure under varying reinforcement spacing, permeability conditions, vegetation coverage assumptions, and hydrodynamic loading. The results highlight that hydraulic conditions, and especially seepage-related pore-pressure development, strongly control stability sensitivity to reservoir level and wave action.