The study explored and discussed the water management strategy of Istanbul with more than 16 million inhabitants. Istanbul has quite limited local fresh water resources with an ultimate storage capacity of 868.7 million m(3) and supplies daily approximately 2.8 million m(3) of water at a magnitude of 180 L/ca. 36% of the water demand is supplied from a water source 190 km away from the city. In this study, the critical balance was evaluated accounting for all important factors, population, expansion; water demand; water quality; protection of water resources. The evaluation was specifically conducted in two major water catchment areas around Buyukcekmece and omerli Basins between 1994 and 2019 using remote sensing technology. The results outlined a significant increase mainly from bare land and green area to artificial surface in Buyukcekmece and omerli Basins with a rate of 217% and 77%, respectively. The conversions to artificial surface were mostly observed to occur in long-range protection zones in both basins. This study also interpreted the potential impacts of the proposed "Canal Project" on water resources regarding the existing and future demands of the population living in Istanbul. The quantitative and qualitative evaluations outlined the fact that the following 5 years of Istanbul will be a critical period in terms of survival and collapse of water management, and that Istanbul needs to enrich its local water resources by generating other alternatives, i.e. sea water desalination from Black Sea or Marmara Sea to compete with the increase of population.