도심열섬현상의 저감을 위한 지속가 능한 해결책으로서의 옥상습지 연구

Abstract

Interests of rooftop gardens are increasing to reduce urban heat island effects and provide ecological space in cities. In this study, I tried to investigate irrigation requirement, plant growth, temperature reduction effect, overwintering and sustainability of pilot-scale rooftop wetland. Two wetland types, one with emerged macrophytes and one with floating macrophytes were created and studied in order to compare the efficiency when used in rooftop gardening. Chlorophyll contents, plant growth, water temperature and other factors were monitored for a two years. Floating plants (Eichhornia crassipes, Pistia stratiotes) grew rapidly, filling the surface completely within a month, and kept growing fast that I needed to harvest half of the plants for several times. In midsummer, the difference in average temperature between water of wetlands and ambient rooftops were about 3 ° C indicating cooling effects of wetlands. As the biomass of wetlands increased rapidly, evapotranspiration of plants would be the reason of temperature drop. On the other hand, water level has reduced much faster than expected. After the first growing season, we left rhizomes of plants unharvested during winter and shoots emerged in spring and revegetated quickly showing that the rooftop wetland could overwinter and sustainable. In conclusion, overwintering ability, great temperature reduction, providing ecological green space makes the rooftop wetland as a very good green area in the urbanized places. Also each emerged and floating macrophyte type wetlands has own advantages for rooftop wetland. Considering each advantages will help to select type of rooftop wetland for future construction.