Urban flooding is a major problem, and effective stormwater management is essential. Hydrodynamic separation (HDS) technologies can be used to remove pollutants from stormwater. There are four types of HDS technologies: screening, filtration, settling, and flotation. Multi-stage hybrid treatment processes with nature-based solutions can be used to improve the efficiency of HDS systems. Future research will focus on hybrid AI-assisted separation technologies, biochar-enhanced filtration, and green infrastructure systems.