Free water surface (FWS) constructed wetlands closely resemble natural wetlands in
appearance and function, with a combination of open-water areas, emergent vegetation,
varying water depths, and other typical wetland features (Wang et al., 2004). Fig. 2 illustrates
the main components of a FWS constructed wetland. A typical FWS constructed wetland
consists of several components that may be modified among various applications but retain
essentially the same features. These components include berms to enclose the treatment cells,
inlet structures that regulate and distribute influent wastewater evenly for optimum treatment,
various combinations of open-water areas and fully vegetated surface areas, and outlet
structures that complement the even distribution provided by inlet structures and allow
adjustment of water levels within the treatment cell. Shape, size, and complexity of design
often are functions of site characteristics rather than preconceived design criteria