Optimum tank size for a rainwater harvesting system: Case study for Northern Cyprus

Abstract

The available freshwater is limited on earth. On the other hand, available water resources on earth have been depleting and being polluted due to climate change and population growth. In order to reduce the risk of water scarcity and water resources contamination, Integrated water resources management (IWRM) is required. IWRM is a concept to manage water resources that aims to balance economic efficiency, social equity, and environmental sustainability. When rainwater harvesting systems (RWHS), one of the techniques of IWRM, are implemented, the stress on water resources is reduced. Since the installation cost of rainwater harvesting systems significantly depends on the size of the rainwater storage tanks, in the implementation of rainwater harvesting, the selection of tank size is one of the main concerns for the feasibility of the system. This study aims to investigate the feasibility of domestic rainwater harvesting systems for a single house. In order to find the optimum storage tank size of the rainwater harvesting system, a linear programming (LP) optimization model is employed. As a case study, the LP model is applied to six regions from semi-arid Eastern Mediterranean island Northern Cyprus, where water resources are limited. The model considers thirty-seven years monthly rainfall data, the roof area of the building, the water consumption per capita, the discount rate, the cost of the rainwater storage tank, and the number of residents. The results of the selected study areas show that the implementation of the RWHS for a single house is infeasible due to the substantial installation costs and maintenance expenses. The financial losses caused by the implementation of the RWHS are found higher than the installation costs and maintenance expenses for all regions. In addition to economic analyses, environmental benefits of the RWHS should be included into the feasibility analysis.