Technical and economic feasibility study of rooftop rainwater harvesting system ) Case Study: Gorgan University of Agricultural Sciences and Natural Resources)

Shortage of freshwater in some parts of Iran is quite serious that needs to be addressed adequately. Rainwater harvesting is considered to be one of the effective ways to reduce the dependence on the conventional fresh water resources. This paper focuses on the feasibility study for implementing rainwater collection systems from rooftops at Gorgan University of Agricultural Sciences and Natural Resources (GUASNR). The paper consists consists of literature review, water balance analysis on two campuses of the university, water quality and microbiology assessment of rainwater for a few samples collected from different rooftops as well as a cost-benefit analysis to determine financial justification. The analysis reveals that rainwater harvesting can reduce the pressure on the municipal water consumption significantly even during dry months. The water quality and microbiology analyses show that careful considerations need to be taken for the possible contamination by pathogens mainly by coliforms and E-coli if drinking consumption is meant. Additionally, in a roof rainwater harvesting system it is essential to design and assemble a filter and a first flush devise properly. The cost-benefit analysis shows that a rainwater harvesting system is economically feasible for the study area although the ratio is negative for a proportion of planning horizon for subsidised pricing. This paper increases the awareness of policy makers and managers of municipal water resources towards knowledge and environmental-based solutions in line with utilising alternative water resources. This can provide the required basis for fund allocation and adequate consideration in policy making and planning programs.