Official

This time, it is a story outside Chuo-ku, but I will write it because there was an anniversary event of infrastructure that benefits the city center including Chuo-ku.
It has been just 100 years since the Arakawa Floodway was passed on October 12, 1924 (Daisho 13). Many people may not be familiar with the name Arakawa Floodway. Divided from the Sumida River in Kita Ward, a 22km long spillway that flows through Adachi-ku, Katsushika-ku, Sumida-ku, Koto-ku, and Edogawa-ku and flows into Tokyo Bay. Until the Meiji era, Arakawa, which flows down from Saitama Prefecture, flowed through the current Sumida River and poured into Tokyo Bay. Following the flood in 1910 (Meiji 43), the Arakawa Floodway was constructed to improve Arakawa's flood response capabilities. The "Iwabuchi Suimon" was installed at the point where the Sumida River was separated from Arakawa, making it possible to regulate the amount of water flowing from Arakawa to the Sumida River during a flood.
After that, due to the land subsidence during the high growth period and the aging of the existing sluice gate, a new Iwabuchi sluice gate (commonly known as Seisuimon) was completed in 1982 (Showa 57). At that time, the old Iwabuchi sluice gate (commonly known as Akamizu Gate), which has historical value, was left without being removed. It seems that various technical considerations and discussions were made. Former Iwabuchi Suimon was designated as a National Important Cultural Property (Building) on August 15, 2024 (Reiwa 6).
The central part of Tokyo, including Chuo-ku, is protected from the flood of Arakawa thanks to various flood control facilities in the upstream and midstream areas, the Arakawa Floodway and the Iwabuchi Suimon. It was on October 12 that the new typhoon No. 19 (2019 East Japan Typhoon) in October 2019 (Reiwa Gen) landed. What a coincidence. At this time, the Iwabuchi sluice gate was closed and prevented the Arakawa flood from flowing into the Sumida River. It may not be well known, but without Iwabuchi sluice gate, the city center was great disaster.
On October 12, 2024 (Reiwa 6), an event to celebrate the 100th anniversary of the spillway was held locally, and many citizens came. . It is very important to know the history of disaster countermeasures and prepare for future disasters. It was a good event with a lot of learning.