Socio-economic considerations of rooftop catchment systems (Case study: Golestan Province, Iran)

Socio-economic assessment of rainwater harvesting systems considered as one of the efficient approaches in water resource management under deficit conditions, leads to a better management practice in the implementation of such systems. This work was aimed at analyzing the socio-economic limitations and potentials of rooftop catchment systems in Golestan province. The methodology was based on field surveying and questionnaire filling at 12 selected sites in Golestan province. Then, each site was hydrologically simulated according to different rainfall conditions, spill over magnitude, number of beneficiaries and volume of demand and reservoirs’ volumes were optimized. To evaluate the economic performance of the rooftop catchment system, Net Present Value (NPV) of a typical site was computed. Results showed that the system would not be economically justified even with a discount rate of 20% during 30 years of simulation. The total cost of implementation of a medium system and its maintenance was estimated to be 70 million Rls., while it only benefits 27000 Rls., annually. This could be a result of low price of water, a fact also confirmed by questionnaires results. Based on the social analysis of rooftop catchment systems, it was revealed that there was a high degree of satisfaction with these systems by residents and users, but it was not welcomed by the new generation of residents in the study area. This issue was mainly arisen from the entry and development of urban and rural water networks which were more convenient to use as compared with traditional systems. There were some other reasons in this background such as low level of knowledge and education about rooftop catchment systems, especially for new generations, as well as the initial cost of executing such systems.