Chichibu-Tama-Kai National Park and Okutama lake


Hiroshige’s image stretches Edo bay in the blur of deep indigo. Okutama is the western-most town in Tokyo and it sits deep in the mountains of the Chichibu-Tama-Kai National Park. Okutama Lake is a a major freshwater source for Tokyo benefiting from the natural flow of the Tama River.


Tokyo’s water supply system goes back a long way, to when a project called Koishikawa Water Supply was established in 1590. The technology was advanced for its time: stone and wooden pipes or conduits carried water to cisterns, water sometimes even flowed uphill thanks to a siphoning effect, pipes were installed in riverbeds, and a network of water mains was constructed throughout the city.