An assessment of the ecological functions of a sustainable structured wetland biotope (SSB)

Abstract

Urban treatment wetlands purify water and provide various ecological services such as food and habitat. We applied the sustainable structured wetland biotope (SSB) system, which considers site-specific ecological conditions and maximizes water purification efficiency, as a treatment wetland for non-point source pollution with short retention time and high biodiversity. This system is consisted of a forebay area (primary retention basin), a micro-pool area (secondary retention basin), and multi-cell structures of marshes and ponds. A wetland constructed with an SSB system for the treatment of non-point source pollution was completed at a site downstream from Jecheon city, located in the upper river basin of the Han River in the Republic of Korea. In addition to the SSB system, a rainwater detention tank for the inflow of the SSB was constructed. During the initial rainfall event, water through SSB were significantly purified (83–98% in BOD, 96–99% in SS, 41–90% in T-N, and 79–96% in T-P of removal efficiency). The flora in the SSB and its neighboring areas consisted of 125 species of 45 families. Three amphibian species, three reptile species, 17 benthic macroinvertebrate species, and 18 avian species were observed in the wetland. We recorded five mammals, including an endangered Eurasian otter species in Korea, Lutra lutra, present in the wetland. Eight fish species were also observed. The wetland showed high removal efficiency without a specific water-treatment device. In addition, local plant and animal species, including rare species, seemed to successfully settle in the SSB.