What's under the manhole covers in the street?
May 28, 2013 7:26 PM   Subscribe

Could the ninja turtles live in Atlanta? What's under all those manhole covers in the street? Is there a giant tunnel under there? Could a homeless person live down there? And why are they constantly digging new holes in the street--what's under the road that a city worker can't access through a manhole, since there are so many?

I'm curious what lies under my streets that requires so many access points. On some roads, it seems like there are covers about every 30 feet. What's down there that they need so much access that they can't just walk through a tunnel (if one exists)?

Is there a whole new world just waiting for me to explore, if only I purchased a crowbar?
posted by wondercow to Travel & Transportation (14 answers total) 3 users marked this as a favorite
Well, by the 90's, it was clear that the ancient water system was collapsing. Sinkholes were opening up and so on. There's been a big overhaul job on that, which may explain why you see so much work.

Where I live now, they did some street work last year, and they put up signs warning drivers about those steel plates in the road. Warning them! How quaint.
posted by thelonius at 7:43 PM on May 28, 2013 [1 favorite]

I don't know specifically what's going on in Atlanta, but if you want a general overview of the sort of stuff that is under streets I recommend Underground by David Macaulay.
posted by Confess, Fletch at 7:49 PM on May 28, 2013 [6 favorites]

Utilities that are underground:
-Large Potable Water Trunks
-Steam, downtown in large cities
-Natural Gas
-Stormwater Retention Tanks
Utilities that may be underground:
-Electric (local)
-Electric (trunk)
-Telephony (local twisted pair)
-Cable TV
-Internet (local)
-Long Distance (fiber optic)

That's off the top of my head. Some major arteries have local and trunk lines of all utilities - and by trunk I mean eight-foot-diameter water mains, sewers and stormwater pipes that are inspected by driving a pickup truck in them, and pairs of wires that carry 40,000 telephone lines on them.
In many of these cases, every time a tee (or equivalent) comes off the main, there's a structure (fancy term for the manhole and all the concrete, block, etc holding it up so you can get to the tee) at that point.
In big cities, electrical switching is done underground, and the transformers are cooled and emit steam from the manholes.
posted by notsnot at 8:36 PM on May 28, 2013 [2 favorites]

If there's a problem, it gets fixed faster if the workers don't have to hike a quarter-mile from the nearest manhole.

Also, Dark Days.
posted by rhizome at 8:42 PM on May 28, 2013 [2 favorites]

Nothing is stopping you if you're actually curious. Older and wiser, one can look back at stupid things one did as a youth and strongly recommend against it, as it is actually pretty hazardous... but it has been done.
posted by rr at 10:01 PM on May 28, 2013

You could live vicariously by reading some urban-exploration blogs— some people who explore them for fun post fairly detailed trip reports. There's some interesting stuff down there, but on the other hand it's mostly just tunnels, pipes, and wires.

Also seconding the Macauley. I suppose it must be out of date, but it gives a good feel for the sheer amount of hidden infrastructure in a city.
posted by hattifattener at 10:30 PM on May 28, 2013

Once, I took a little trip to underground Asheville. Long story, but it was to check to see if a company was dumping toxics into the storm sewer. Went about 1/2 mile through storm sewer past where the storm sewer hookup was near the company in question. I was recruited at the last minute to go when pre-Mrs. Fauxscot, who shall remain nameless, wussed out when confronted with a 12 foot ladder into the unlit darkness of the underworld. The partner who didn't wuss out was determined to go alone, and I could not stand by and let that happen, so in I went. I am an easily influenced idiot sometimes. OK, often. OK, generally.

As expected (since I knew the company), there was nothing, because they had plenty of positive and negative economic incentive for them to not dump their waste. However, I entered the system with another enterprising friend, a cute and brave woman, and she and I went immediately from a modern entry port into a patchwork of underground tunnels, creeks vaults and hazards obviously from every era that the city had. There was bare creek below, complete with rocks, pools, and brisk water, brick vaulting from the 1800's, new concrete sections, little connectors with adjacent conduits, and highly variable headroom/body room. Roots and in a few cases, eroded shards of pointy sharp rebar and metal protruded into our path, and frankly, at this point I am retroactively aware of how dangerous it was and how quickly our little jaunt could have been a serious puncture wound experience and/or stuck explorer situation. We went as a team, of course, with an above-ground element who had my cell phone and a radio, the latter quickly useless. We had to exit via a pretty thin slot and looked like a couple of crazies, zombies, perhaps. There were a few really puzzled people who watched us arise out of the ground in front of their apartment.

You can explore, of course. Hell, when I was a kid (pre-teen) we used to take extremely unwise trips that adults were unaware of that could have easily gone very, very wrong and survived.

I would generally advise reading about it, however. Air quality, light, disease, toxics, critters, dirt, dangerous energy, and confined places are the common risks. In any remote area that encompasses significant volume of space, if you find it, so might someone else and you have that set of issues to confront. What kind of folks might you expect who aren't innocent explorers? Transportation conduits I would expect to be kind of shady. They exit to the outside a lot, which means they have entry potential for lots of folks of diverse origins and charters, to put it midly.

There is a ton of interesting stuff you can see above ground. Folks venture down a lot, and I would think you'd want to do with with a tour guide who had been there before. Like tunneling or wilderness hiking, leaving someone on top who knows what the deal is and who can summon assistance if problems or timeouts arise would be really good. Tools, lighting, first aid, and a boatload of caution would be useful, but will not make up for the questionable judgement of doing this. Still, you gotta die somehow and this is as good a way as any to get it over with.
posted by FauxScot at 12:16 AM on May 29, 2013 [5 favorites]

The coolest thing about manhole covers is the enameled ones in Japan.

The second coolest thing is that the ones in Rome say SPQR on them.
posted by Bruce H. at 3:30 AM on May 29, 2013 [2 favorites]

Are you talking about actual manhole covers ( I haven't noticed an excess of them ) or the big steel plates that are everywhere covering the many, massive pot holes in our streets? Atlanta has some serious issues, street quality being high on the list.
posted by pearlybob at 3:36 AM on May 29, 2013 [1 favorite]

They could just be vents for the sewer system.
posted by gjc at 4:01 AM on May 29, 2013

And why are they constantly digging new holes in the street--what's under the road that a city worker can't access through a manhole, since there are so many?

Well, there aren't tunnels everywhere that pipes and wires exist. Sometimes they just dig a trench, lay in the pipes or wires, back-fill with soil and pave over it. Digging is often the only way to get to a broken spot, or to make a new connection.

Also, some of the iron covers aren't really intended as places a person can climb into; sometimes they're just openings to access something like a valve or a pipe cleanout close to the surface.
posted by jon1270 at 4:07 AM on May 29, 2013 [3 favorites]

Basically, this is a classic case of "we should have been smart from the very beginning, but, uh, we weren't, and meanwhile now we'd rather not have to dig up whole streets, so, let's dig lots of individual holes if we can for now."

OK, maybe it's only classic if you deal in public works on a regular basis.

Anyway, know how the gas and electric companies are always saying "Call Before You Dig" because there's all kinds of crap in your yard that you can't see, and you might die or break things if you hit it while you garden or install a pool or whatever? Same deal with the roads.

There are often five to ten different agencies/companies out there putting their stuff under the roads, and all of it is bigger and more complicated than what's in your yard (and it all services a heck of a lot more people.) We put it in the middle of the street because what we what we make the roads out of is easier to fix than sidewalks, and it's all in the "right of way" so they don't have to hassle with individual property owners. Unfortunately, it's still not cheap or easy to rip up roads all the time - periodically you see the water/electric folks get in trouble for not coordinating massive fixes with the roads folks, because it costs millions of dollars every time you rebuild the whole entire street; it doesn't get cheaper the second time you do it in a year.

Bottom line: whenever possible, we try to dig just one hole, as small as possible, to get the job at hand done and make it easier to do a very similar job next time (especially if closing the street will cause yelling at a city council meeting.) Unless you're in a subway-filled city like NYC or Paris, or at Disney World, the adventure opportunity is limited (I'd be terrified to try in NYC because ugh and also trespassing, but "adventure" doesn't mean "wise," so.)

Some cities make a stronger effort, when doing a full rebuild of the road, to put easier access in underground for utilities and such. I can't remember if the feds put in any incentives for that kind of thing in their grants; I don't remember seeing any in the stimulus stuff a few years back, but I wasn't looking out for that, so.

And please leave the manhole covers alone (the big round ones.) They're expensive and really really heavy; moving them is pretty high on the list of things that road crews accidentally get hurt doing.
posted by SMPA at 4:51 AM on May 29, 2013 [2 favorites]

Fellow Atlantan here. Those huge metal plate are the jacked up way the city deals with potholes.

Also, as thelonius points out, our water system is TERRIBLE! In my little neighborhood, the Public Works department is forever fixing something. At least once a week there's clay in the lines because of digging they've been doing.

I'm kinda bummed. I'm having plumbing problems at my house so I'm not feeling very charitable about Atlanta Water right now.
posted by Ruthless Bunny at 6:29 AM on May 29, 2013

Best answer: I work for a local city government in our IS department (I do GIS work). and often talk to our sewer department for various projects. Whats actually under the sewer manholes, at least in my city, is not that exciting. Directly underneath is a large chamber big enough for a person to fit into, but most of our lines are less than a foot in diameter. Some of the bigger lines are a few feet in diameter. I have seen some possums crawling around the pipes, but not much else, there's just not enough room. We inspect the lines by sending cameras on wheels through them.

We also still have plenty of "lampholes" lying around. Lampholes are not big enough for a person, but back in the day, before the cameras on wheels, one inspector would be at a manhole while the other would lower a lamp tied to a rope down the lamphole. If the inspector in the manhole could see the light fairly well, then the line was free of blockage. The sewer system is pretty much a closed system here, as I imagine it is in most cities around the US. Leaking sewage is a big deal.

The stormwater system however is different. Culverts channel stormwater from drainage basins out of the city, and some of these are very large. Theres a wide variety of things to encounter there besides leaves and trash - animals, runaway children, homeless adults, syringes, etc.

If I could imagine the Ninja Turtles making a home underneath a city, they would have more room in stormwater channels than the sewers. Other than that, as others have mentioned, a lot of big old buildings like schools will have large steam pipe tunnels.

I know that depending on ground conditions and climate it may be better for cities to put everything in utility tunnels, like in Alaska, where the frost line can be very deep underground.
posted by ajax287 at 5:52 PM on May 29, 2013

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