Storage Capacity Design of Rainwater Utilization System for Green Roof in Buildings

• Main Authors: Shih-Chieh Lin, 林仕傑
• Other Authors: Chao-Hsien Liaw
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/27672692213362571949

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 99 === With highly urbanization in majority of cities in Taiwan, a lot of vegetated lands have been replaced by impervious pavement which causes series of environmental problems. However, restoring impervious pavement into vegetated land is difficult because of high cost of land, high density of population, etc. Among all alternatives, green roof is the most available method to replace the vegetated land. But the water demand for irrigation of green roof will increase the problem of water supply. Therefore, rainwater harvesting system will be one alternative for water supply for green roof. This research tries to develop a framework to estimate the storage capacity of rooftop rainwater harvesting system by the factors of demand and supply and climate data for northern part of Taiwan. In the system, demand is determined by evapotranspiration and supply is determined by the placement of green roof. The correction factors (K) for evapotranspiration and runoff coefficient (C) for roofs are both obtained from experiments. GIS is used for estimating climate data if there is no weather station and rainfall data at constructed site, As a case study, 100 m2 of green roof is installed on the rooftop of the 2nd building of Department of Harbor and River Engineering, National Taiwan Ocean University. The required rainwater storage capacity for selected reliabilities (10%, 20%, 30%, 40%, 50% and 60%) are 0.08, 0.17, 0.25, 0.53, 1.24, and 3.40 m3, respectively. Rainwater storage capacity increases dramatically with higher reliability. For other counties in the northern part of Taiwan, required rainwater storage capacity have the same tendency as the results of the case study.