Introduction:
Coasts, as sensitive ecosystems and diverse habitats, require protection. Human activities and climate change can exacerbate erosion and degradation of these ecosystems. Understanding water flow patterns and sediment transport is crucial for developing effective solutions for coastal management and reducing of hazards from storms and sea-level rise. Coasts, as the interface between land and sea, are influenced by water flows, sedimentation processes, and erosion. Fluid dynamics theories, such as the Navier-Stokes equations, describe the behavior of flows and their impact on sediment distribution. Sediment transport models, such as equilibrium sediment models, also aid in analyzing sedimentation and erosion mechanisms. Environmental and climatic impacts, especially through climate change models, add new dimensions to this topic.
 Methods:

 Coastal communities rely on gray infrastructure such as breakwaters and seawalls to reduce flood risk. These structures absorb and deflect wave energy, but they can impact the morphology of downstream currents. Breakwaters are located on sandy beaches and trap sediment on their landward side, but they can increase erosion on downstream beaches. Offshore breakwaters are located in deeper water and reduce sand flow, but they can intensify wave action in unprotected areas. Seawalls are used to protect coastlines; however, they can increase erosion and expose inland areas to flood risk. Wave control structures cannot sustainably manage flood risk, and require high maintenance costs. These structures fragment and destroy natural habitats and have limited ecological function. Moreover, they cannot adapt to climate change and rising sea levels. Using vegetation to increase coastal resilience and reduce the impact of floods is a promising approach. However, little information exists regarding the longevity of vegetation for flood risk management, so further research is needed. Coastal vegetation is recognized as an effective defense against natural and human disturbances. These plants support diverse ecosystems and provide habitats for various species. Mangrove trees, with their complex root systems, create shelters for mammals, birds, and reptiles. Salt marshes are also productive ecosystems that support unique plant and animal species. Seagrasses provide important habitats for marine life and contribute to the life cycle of aquatic organisms. Coastal vegetation plays a significant role in mitigating the effects of climate change and accounts for 14% of the carbon dioxide absorbed by oceans. Seagrass beds comprise 10 to 18 percent of the total ocean carbon storage. These ecosystems help stabilize the coastline and prevent erosion by retaining sediments. White mangroves in Iran enhance soil stability and prevent coastal erosion. Overall, coastal vegetation is effective on reducing flood risks and provides environmental and climatic benefits.
 Results:
This research evaluated the role of vegetated coastal habitats in flood risk management, focusing on their mechanisms, benefits, and challenges. Coastal areas, home to more than one-third of the world's population, face growing flood risks due to climate change, including sea-level rise and increased storm intensity. While traditional solutions such as breakwaters and seawalls are effective at a local level in reducing coastal flood risk, they pose significant long-term environmental problems, including down-drift erosion and increased vulnerability to flooding. In contrast, vegetated areas such as mangroves, salt marshes, and seagrass beds offer opportunities as sustainable alternatives for flood risk reduction, functioning through wave attenuation, sediment stabilization, and storm surge reduction. Furthermore, these solutions provide multiple benefits, such as promoting biodiversity, improving water quality and facilitating carbon sequestration. However, implementing vegetation on a larger scale faces various challenges, including: ecological and environmental limitations related to the response, behavior, and dynamics of coastal ecosystems; socio-economic and policy limitations; and a lack of empirical evidence regarding their effectiveness and sustainability within the timeframes required for coastal management. Moreover, evaluating and measuring the long-term effectiveness of these solutions in flood and inundation risk management remains challenging due to insufficient empirical data and the complexities of coastal systems.
 Conclusion:
This review examined studies on coastal protection, focusing on flow patterns, sediment transport, and coastal flood control through vegetation such as mangroves, seagrasses, and salt marshes. The interaction of vegetation with waves’ dynamics, challenges, uncertainties, and data scarcity for vegetation-based coastal flood protection were also discussed. The results of this review could contribute to the developing sustainable and effective solutions for coastal management and protection.