What are the main sources of water in Istanbul and how is the city managing its water resources to ensure sustainability and availability for its residents?

The main sources of water in Istanbul are surface water from dams and reservoirs, as well as groundwater from wells. The city is managing its water resources through various strategies such as water conservation measures, infrastructure improvements, and diversifying water sources. This is to ensure sustainability and availability of water for its residents, especially during periods of high demand or drought.