A subsurface flow (SF) wetland is specifically designed for the treatment or polishing of some type of wastewater and are typically constructed as a bed or channel containing appropriate media. The main advantages of this subsurface water level are prevention of mosquitoes and odors, and elimination of the risk of public contact with the partially treated wastewater.
EPA (2000): Wastewater Technology Fact Sheet - Wetlands: Subsurface Flow. Washington D.C.: United States Environmental Protection Agency (EPA) URL [Accessed: 06.09.2012]