Please note that the manhole cover is slippery on rainy days!

Yokohama City had an international trading port, so in 1869 it began to develop sewerage systems earlier than in other cities as a sanitary measure for foreign settlement. After that, maintenance was delayed due to the Great Kanto Earthquake, World War II, etc., but in 1957, full-scale sewerage maintenance with a final treatment plant was started, and the sewer penetration rate at the end of March 2005 was 99.7%.

The sewer that has been maintained in this way has built a huge network in underground spaces such as roads, but I think that only the manholes on the road are directly visible to citizens.

In addition, sewer manholes are installed to perform maintenance such as pipe inspection and cleaning work, and the number is about 510,000 in the city alone.

By the way, with changes in road conditions in recent years, such as an increase in large vehicles, cast iron lids with high strength and durable cast iron lids have been adopted nationwide for manhole covers to prevent vibration and noise caused by vehicle traffic. .

Yokohama City has more hills compared to other cities, so the roads are relatively steep. For this reason, the manhole cover has a pattern on the surface as a countermeasure against slip, but please be careful as it may slip depending on the type of shoe soles such as on rainy days.

In addition, in order to respond to pedestrian measures and barrier-free for the aging society in the future, we will consider measures to prevent slipping on the steep slope manhole cover.