A probabilistic approach to rainwater harvesting systems design and evaluation

• Main Authors: Chun-Hung Lin, 林俊宏
• Other Authors: Ming-Daw Su
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/93221405802603675143

博士 === 臺灣大學 === 生物環境系統工程學研究所 === 97 === The imbalance among water supply and demand becomes a more and more serious problem in Taiwan owing to rapid growth of population and socio-economic activities. Rainwater harvest is an alternative water supply source to relieve this water shortage pressure in urban area. Since the effectiveness of Rainwater Harvesting System (RHS) design is heavily dependent on rainfall characteristics, both optimization and simulation were used to approach this problem of storage design for RHS. In the past, most of the studies present the average successful rate under a specific storage capacity. This paper presents a probabilistic analysis approach to construct the supply deficit probability distribution under a designed storage as well as the exceedence probability curve of deficit rate under different storage capacities. The fitted probability density function was transformed into exceedance probability (EP) curve for reliability evaluation on RHS designs. A more effective RHS design may be achieved and relieve regional water supply pressure. This information provides a holistic view of the RHS performance characteristic for more effective RHS design. In this research, cities of Taipei and Tainan were used as study areas for the demonstration of this methodology. Subsequently the probabilistic distribution curves for relationships between storage capacities and deficit rates as well as the relationships between storage capacities and system evaluation index were presented. The results show that deficit rate and comprehensive evaluation index is lower in Taipei with 0.2 （m3/m2） than in Tainan with 0.6 （m3/m2）. It indicates that the system requires larger storage capacity when ratio of high rainfall to low rainfall is higher.