Handbook of Water Harvesting and Conservation

23Rainwater and Green Roofs

Sara Nazif¹, Seyed Ghasem Razavi¹, Pouria Soleimani¹, and Saeid Eslamian²

¹School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran

²Department of Water Engineering, College of Agriculture, Isfahan University of Technology, Isfahan, Iran

23.1 Introduction

In urban areas with a considerable amount of impervious areas, green roofs can be effectively used for natural runoff management in urban areas in addition to other runoff management practices. In other words, the green roofs help in enhancing or restoring the natural hydrologic cycle in urban area (Dayani et al. 2017). A small amount of water is used by vegetation on the green roof; however, the growth media will store a significant amount of water. The stored water in the saturated soil will be slowly released; therefore, it helps reduce the risk of a flash flood. Furthermore, they can be effective in improving the quality of urban runoff.

Green roofs, or living roofs, have been used for a long time, but recently, with the advancement of technology and improvement of their installation and construction, people are particularly attracted to these roofs. These roofs are more likely to be built on low-rise buildings because of security and safety issues (Herrera-Gomez et al. 2017). By understanding the benefits of green roofs in recent decades, they are widely spreading among countries around the world such as Singapore, Canada, the US, Japan, and Hong Kong. Many cities ...