Chuo-ku Tourism Association correspondent blog

The current Sumida River is downstream of Arakawa, a first-class river, and is divided into the Arakawa Floodway at Iwabuchi near Akabane and pours into Tokyo Bay.
However, the flow of the river before the Edo period was completely different from now. The Tone River, which now flows into the Pacific Ocean in Choshi, used to be a river that flows to Tokyo Bay. A part of the flow of the Tone River at that time is the water surface of the "Ko Sumida River" that currently remains at the border between Adachi-ku and Katsushika-ku.
Since Ieyasu Tokugawa entered Edo in 1590, large-scale river replacement work has been carried out. Due to the east transition of the Tone River, the separation of the Arakawa and Tone Rivers, and the excavation of the straight waterway of the Ayase River, the "Ko Sumida River" is no longer the main channel.
　
Many of the waterways that were often stretched in Chuo-ku were reclaimed by earthquake reconstruction, war reconstruction, and the Tokyo Olympics, but the water surface of the old Sumida River still remains as valuable waterside space in the city. It is a few minutes on foot from Tokyo Metro Ayase Station. It can not be imagined from the current scenery that this was once a great river, but the thoughts and difficulties of many engineers in the past who worked hard to rule the river and create a city where people can live easily, I think it should be handed down to future generations.