Marshes are freshwater wetlands characterized by saturated soils and vegetation that is adapted to anaerobic or anoxic conditions. These ecosystems are integral components of regional hydrology, functioning as natural filters that slow and purify flowing water, thereby mitigating runoff and sedimentation. The unique root structures and biomass of marsh plants help stabilize soft substrates and effectively reduce the intensity of natural erosion processes. Ecologically, marshes are critical sites for nutrient cycling and support complex aquatic and terrestrial biodiversity, making them vital components of global wetland networks.