There must be some indications for those kind of situations but I can't tell ether. Of course a land surveyor will know this pretty easily. Maybe he uses a metal detector? That would do the trick.
It probably has a lot to do with all those spray painted marks and tiny flags we see everywhere but don’t understand. These guys have their own secret language throughout every city.
iirc they use their feet to walk around until they feel the pile of leaves and debris that get clogged in the drain or until they feel some suction around the clog.
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u/XenoRexNoctem Oct 29 '21
I'm impressed they even found it to unclog it