Rainwater Harvesting as an Alternative Water Source in Semarang, Indonesia: The Problems and Benefits

One of the obvious impacts of climate change is the vulnerability of clean water availability due to uncertain weather conditions marked by the shift in periods of rainy and dry seasons. Semarang is a coastal city with a diverse topography that faces challenges of clean water supply. Semarang’s residents living in hilly areas still rely on non-piped water as a source of clean water which, in turn, affects ground water availability. On the other hand, rainwater runoff can cause flooding due to the limited extent of non-built-up areas for water infiltration. The Association of Cities Climate Change Resilience Network (ACCCRN) has initiated a pilot project to implement a rainwater harvesting (RH) system which could increase Semarang’s resilience in clean water provision. The communal RH model was applied in Tandang Village, while the individual RH model was implemented in Wonosari Village. This paper aims to explore the problems and benefits of the use of the RH system for both models. This study applies a mixed method approach via interviews with all relevant stakeholders and questionnaires for rainwater harvesting users. The study found that problems that arise are the perception that rainwater is only fit for non-consumption needs, the community’s willingness to utilize rainwater depends on the availability of other alternative water sources, the high installation costs for the poor especially for the individual models, and the challenge of the community’s willingness in managing communal systems requiring collective participation. The benefits of using RH can be seen from the cost savings for clean water, the formation of social capital from collaborative efforts of managing the communal RH system, and the reduction of rainwater runoff as one of the factors that cause floods.