When you run a new utility line, whether it be electrical, gas, water, sewer, or communications,
you basically have two choices for where to put it: overhead strung across poles, or below
the ground.
Today we’re talking about that second one, subsurface utilities.
I’m Grady and this is What’s that Infrastructure, where we divulge and discover the manmade
world around us, and below us too.
There are all kinds of utility lines running beneath our feet under roads, sidewalks, buildings,
and property connecting resources to the people who use them or in the case of sewers, carrying
wastes away from people so we don't get sick.
There are distinct advantages to running utilities below the ground: for one, it’s often the
cheaper solution when compared to other options, also, subsurface utilities are hidden so they’re
less likely to be vandalized or detract from a place's appearance, and finally they’re
protected from weather like freezing temperatures and high winds.
We have just about every resource you can think of running in subsurface utilities,
including electricity, oil and natural gas, water, sewage, telecommunications and many
more.
Here’s a couple of underground utilities that you don’t see as often.
Tero from Finland sent in this photo of an automated vacuum waste collection system in
Helsinki.
He said it’s basically a packet switched network for trash bags, since each of these
collection points feed to the same underground vacuum pipe.
And Stephen from Pennsylvania sent in another one you don’t see often.
These pipe are part of a snow melt system which will run a warm liquid to prevent this
sidewalk from icing up during the winter.
Speaking of winter, Andrew from Newark sent in this photo of a hydrant with a long pole
attached.
During the snowy season, the plows clearing the roads pile up huge banks of snow
covering up the hydrants.
In the event of an emergency, the hydrant can quickly be identified by this marker and uncovered
from the snow so that firefighters don’t have to search for it.
As our urban subsurface gets more and more crowded with underground utilities, the possibility
of conflicts or damaging an existing line increases.
Surprisingly enough, there is no clearinghouse of information documenting the location of
all subsurface utilities, at least in the US.
And the dangers and potential costs associated with damaging something like a water line
or fiber optic cable are so high, that an entire new field of engineering has emerged
just to manage the risks: Subsurface Utility Engineering (or just SUE for short).
SUE specialists use a handful of methods to identify and locate subsurface utilities.
Many public works projects rely on SUE data to avoid conflicts with underground utilities
during construction.
A SUE survey can be as simple as drawing a straight line between manholes but many utility
location surveys involve sophisticated investigation techniques like vacuum excavation and even
ground penetrating radar.
You’ve probably seen these cryptic spray paint marks locating utilities after a SUE
survey.
In fact, the symbols and colors used are fairly standardized by country.
Here’s a photo Doug from Sacramento sent in of a SUE survey locating a combined streetlight
and communications conduit below a sidewalk.
Some jurisdictions are requiring buried utilities to include sophisticated new identification
systems.
Adam sent in these photos of an RFID utility marker in Slovakia.
This marker gets buried with the utility lines so that they can be accurately located if
someone ever needs to dig here again.
Utilities below the ground sometimes need access to air, usually to avoid the buildup
of pressure.
Sanitary sewer systems are meant to flow by gravity, so if the pipes are properly vented,
they work better, just like venting a bottle will allow it to pour more quickly.
This is a manhole vent sent in by Joel.
If the top of the manhole is below the floodplain, a riser pipe is often required to make sure
the line is vented even during flooding conditions.
Most gas stations store gasoline in underground tanks below the pumps.
The tanks need vents so that they don’t pressurize during the heat of the day, so
they also have vent pipes like these sent in by Jaron from Lincoln Nebraska.
Here’s a few more vent pipes sent in by Marty from Vancouver, but he wasn’t sure
what specifically they were venting.
Speaking of things that I can’t identify, here’s a couple more.
If you know what they are, let us know in the comments.
Timon sent in this photo of a pipe that isn’t subsurface at all, but is actually running
overhead on poles in Berlin.
Pipes carrying liquids are rarely placed above ground in areas that can freeze.
That and the lifting hooks on the concrete blocks make me think this is a temporary installation
of some kind.
Finally, Bert sent in this photo from a beach in Belgium.
This is obviously an intake screen, but I have no idea what would be drawing sea water
this close to the shore, or why it would be installed above the low tide.
Put a comment if you think you know.
Thanks again to everyone who sent in photos.
It makes me really happy to discover that so many people are interested in videos about
infrastructure, and it is really encouraging to receive so many enthusiastic emails.
If you’ve got a picture you’d like to share, send it in to Whats.That.Infrastructure@gmail.com.
Make sure you mention that it’s okay for me to use in a video, and include your mailing
address.
Because if I use your photo in a video, I’ll send you a Practical Engineering sticker.
I’ve got some very cool videos in the works, so if you like this kind of stuff, subscribe
to the channel.
Have a great new year, and as always, thank you for watching, and let me know what you think.