Enabling widespread use of rainwater harvesting (RWH) systems: challenges and needs in twenty-first-century Istanbul

Water supply has been a chronic challenge in Istanbul since its foundation. Authorities have sought alternative methods since the Roman and Byzantine periods. Cisterns, channels and wells surveyed in urban heritage sites in Istanbul provide evidence of rainwater harvesting (RWH) as a working solution in the past. However, RWH systems have only been utilized in contemporary plans and policies very recently, particularly since the climate change crisis entered the political agenda in Turkey. Taking this as a point of departure, this paper investigates the challenges of widespread implementation of RWH systems in Istanbul through a participatory inquiry with water management actors. Challenges and needs are explored through a set of in-depth interviews and participatory workshops with representatives from water management institutions. The findings reveal that current challenges are related to planning and development, legislation and governance, financing, society, infrastructure, installation and operation of systems. The potential solution is the establishment of a governance mechanism that enables collective action among relevant actors.