Assessment of Reliability Variations of the Rainwater Catchment System Using Future GCM Output Data (Case Study: Birjand City)

Evaporation loss is a key component of water resource management in arid and semi-arid regions where they are not uniformly distributed temporally. Also, due to the climate condition and physical characteristics of arid areas, a major part of rainfall will be out of reach in the form of flash floods and a few percent is recharged to groundwater aquifers. Rainwater harvesting system (RWHS) is considered as one of the most instrumental techniques that can save rainwater for domestic or agricultural uses. It is a technology used for collecting and storing rainwater in rooftops, land surfaces, or rock catchments using some simple techniques, such as natural and/or artificial ponds and reservoirs. In recent years, climate change has caused significant changes in the meteorological and hydrological components. Also, since precipitation is the main driver of RWHS, changes in its value and time can significantly change the operation of these systems. Therefore, in order to reach sustainable development, water resource management based on rainwater harvesting systems will be inevitable. These systems are moderately reliable methods to increase available water. The main aim of this study is the reliability assessment of rainwater harvesting systems designed for a future period (2017-2030) in Birjand, the center of Southern Khorasan Province, east of Iran.