Official
Why a boat tour of the river
The stories about rivers heard from civil engineering engineers
On October 7th, I participated in a tour where I could learn about the rivers of Edo and Tokyo from a boat ride guide.
This was the ninth adult social studies tour, but it seems that it was held for the first time in three years due to the COVID-19 pandemic.
The day was cold in the latter half of November, and the temperature was about 12 degrees Celsius, and it was a tour while the rain continued to fall strongly, but the inside of the ship was surrounded by roofs and vinyl, so I was able to tour without feeling the cold .
What is "waterfront" as the route that Tokyo Dumbo participated in? "Course 2" is a course to learn the role of urban waterside space," which departs from Nihonbashi Pier, crosses the Sumida River, goes east along the Onagi River in Koto-ku, turns north from the Yokojikken River, enters the Kitajukken River, and is the starting point of the Sky Tree.
In this course, we proceeded toward the Koto Triangle Zone, a zero meter above sea level.
As can be seen from the floor plan and cross section, the dike will be high if the ground is low, but it will be too high, so it will be managed so as not to be affected by the water level at the sea level (in this case, Tokyo Port) by setting up a sluice or lock.
In Chuo-ku, the AP is about 3m, but in the Koto Triangle, it is less than –1m.
There is a considerable height on the embankment of the Sumida River around Chuo-ku, but if you try to maintain the height as it is, you will need a height of about 10m.
※What is AP?
This is a numerical value indicating the height. Arakawa Peil is an abbreviation, which is called Arakawa Construction Standard Surface. It is determined at the lowest water level of the water level station on Reigishi Island in Shinkawa, Chuo-ku, Tokyo.
Before and after the Shin Onagi River Sluice Gate on the way, there was a difference of about 2m in height of dike.
Further east, there was the Ogibashi lock gate. This is a facility that can be called the "Mini Panama Canal," which allows ships to pass through rivers with different water levels. By artificially changing the water level of a waterway called locks sandwiched between two sluice gates (front and rear doors), the water level dropped by about 1m in about 6 minutes, and further eastwards.
This water level adjustment is carried out by Tokyo, and tolls are not taken.
Departing from Nihonbashi to the Sky Tree, you can not only enjoy the scenery, but also the attractions of the Mini Panama Canal, so I felt that this would be a very fun boat tour.
※Please refer to the Ogibashi Lock Gate pamphlet issued by Koto Flood Control Office, Tokyo.
The guide of this tour was Mr. Onuki of Construction Technology Research Institute Co., Ltd., a 26-year-old technician specializing in river surveys and planning, and was explained very clearly. There was also a story from the captain about the operation of the ship, which was also very fun.
Construction Technology Research Institute, Ltd. is Japan's first construction consultant, which was founded in 1945, and is a comprehensive construction consultant who has been leading the industry for many years as a leading company and competes for the top market sales in Japan. In particular, a consultant in the river field has been able to contribute to comprehensive management of the entire basin, including disaster prevention and antidisaster measure planning for floods and droughts, and conservation and improvement of the water environment and water circulation for many years.