I’ve been pretty interested in manhole covers for the last week or so. I read about them in the brilliant The 99% Invisible City and since then, well, I’ve gone down the manhole, as it were.
The 99% Invisible City talks about the movement – a Japanese trend for decorative manhole designs displaying “location-specific motifs” and everything from Hello Kitty to elements of folklore. Back in the eighties, the original impetus for this stuff was to raise awareness of subsurface utilities at a time when only half of Japanese households were connected to municipal sewers. Since then it has become a thing of joy and creativity in its own right.
My sister was once very excited about a manhole cover in Canterbury that had a spelling mistake on it. But there is so much more to be intrigued by. Outside of Japan, I was fascinated to discover that the cross-hatching patterns a lot of manhole covers have is to aid traction. Yet that is just the start.
Here’s what really got me: according to 99% Invisible, in Seattle, some manhole covers have city maps on them. In Nashua, New Hampshire, the triangular covers “point in the direction of subsurface flows”. This has really stuck with me for some reason, and I think I know what it is.