A mini 'Panama Canal' in Koto City

the front gate of the Ogibashi Lock

When you want to go by boat from the west side of our city to the east side through the Onagigawa Canal, you have to go through two lock gates, mechanism of which is similar to that of the Panama Canal.

You might think it odd that there are locks to control the level of water in this flat land of Koto City near the Tokyo Bay.

The reason is that we have areas lower than the sea level because of heavy pumping of ground water for industrial use by large factories established late 19th century when modern Japanese industries began to grow, until mid 20th century when they are moved outside of Tokyo.

the back gate of the the Ogibashi Lock

As a result, a large area sank below sea level. People living there repeatedly suffered from flooding from heavy rain or storm surges.

Now the lowland areas are protected from flooding by floodgates on all internal canals. Locks are built for pleasure boats, canoes, barges or other boats to go through. The water level of the lowland is always kept 1 meter below the lowest tide of the Tokyo Bay.

When you want to go by boat from the Sumidagawa to the Arakawa River on the Onagigawa Canal;

Arakawa Lock Gate

1)You pass through the front gate of the Ogibashi Lock and wait until the front gate closes and the water level is lowered enough to the same level with the internal canal.

2) Then the back gate of the lock opens and you can go on.

3) Soon you will reach Arakawa Lock Gate. You will repeat the same procedures in 1) and 2). But this time the water level is raised and you can successfully go onto the Arakawa River.

If you are interested to see the lock gates, please refer to the access maps in the following URLs (written in Japanese).

Ogibashi Lock: http://koto-kanko.jp/theme/detail_spot.php?id=S00156

Arakawa Lock Gate: http://koto-kanko.jp/theme/detail_spot.php?id=S00095

(by Hiroshi)

Share this post