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UER Forum > UE Encyclopedia > Drain (Viewed 11099 times)
Entry: Drain
originally posted by F A S T

[last edit 10/19/2012 2:33 AM by RescueMe1060 - edited 63 times]

Storm Drains


Storm Drain: Carries urban run-off to a body of water. Usually this water goes untreated, though in some cities UV treatment is used during dry months.

Inlet: Pipe that water flows into from a river or lake. Also known as infall.

Outlet: Pipe that water flows out of into a body of water. Also known as outfall.

*Generally as you head upstream in a water system the pipes will get smaller as they are expected to carry less water.

Temperature: Most drains remain slightly warmer than room temperature year around. This applies to most underground tunnel systems.

Sanitary Sewer: Carries wastewater. Sinks, showers, toilets...

Combined Sewer: Carries stormwater and sanitary waste.

How to locate a drain

Obtain a watershed map for your area and find all the creeks. You can use a topographical map as well to determine the amount of waterflow in the creeks and thus a rough estimate of whether or not the drain is large or small.

Follow the creeks and look for locations where they vanish, or flow under cities. Some watershed maps will show you where the creek becomes culverted.

An example of a watershed map can be found here:

Tunnel Types:

RCP: Reinforced concrete pipe. Its a circular concrete pipe. Also called round concrete pipe.

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CMP: Corrugated metal pipe. Usually used in smaller drain systems where concrete really isn't necessary, however it is also used in medium/large drains systems as well.

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RCB: Reinforced concrete box. Often you "double barrel" forms of these. Sometimes the floor will have inclines towards the center in these.

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RBA: Red brick arch. Red brick is becoming uncommon these days. Often arches are also made of concrete.

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Subway: This is two flat, elevated platforms with water flow in the center.

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Mummy/Coffin/Horseshoe: This has an arched ceiling and a floor with inclines on either wall and a flat bottom. It's been said that this tunnel type is becoming more and more uncommon.

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For more photographic examples of these and others visit:

Other features:

Slides: Slides are when the tunnel loses elevation and the pipe angles downwards.

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Stairs: Also used when the pipe loses elevation, only instead of a slide stairs take the water down. Stairs tend to be found more commonly in areas where there is higher waterflow. There they are more useful to slow water currents.

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Falls: These may be used to drop the drain in elevation, and/or they may be used to slow water currents during wet weather periods.

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Sidepipes: These are smaller pipes that carry water into the mains. Water that collects in gutters generally flows to a sidepipe, which eventually flows to the main drain.

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Grille Rooms: These are large rooms with grills for a ceilings. The grills allow water to flow in from major paved areas during storms. These rooms offer light and often have an exit as well.

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Manhole Chambers: A chamber that has a manhole cover at the top. These chambers are usually larger than the tunnels surrounding them, and offer a chance to stretch.

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Manholes: Manholes are entry points to drainage systems for public works. They vary in weight depending on their location. Generally manholes in roads will weigh more than manholes off roads. It's best not to open manholes from within a drain because there's always the chance it's on a street. It's theoretically impossible for a circular manhole to fall in on you, but with the square/triangular ones you never know.

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Pillars: Pillars used for support and/or to absorb some of the mechanical energy generated by storms.

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GPT's Gross pollutant traps. These are holes in the drain that collect heavy objects. They also make the water level rise until you pass them.

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Gutters: Also known as rainslots, these metal structures capture street runoff. Most gutters flow to sidepipes, which in turn flow to the main drain. Occasionaly the main drain will flow under a gutterbox, and the water will be deposited directly into it. Generally the goal engineers have when designing gutter box's is to allow the maxiumum amount of water in, and minimize the amount of trash getting in. Of course, if they made the water entry to small then the trash would clog it, and the street would flood.

Rungs: Rungs are used to make drains man passable. Also known as stepirons, you may find them by falls, manhole chambers, and grille rooms. Many rungs are rusted or in disrepair, its best not to trust them.

Wildlife: Rats, bats, crabs, racoons, skunks, fish etc. There are many animals that live in drains. AVOID THEM! See hazards section for more information!

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Consider all the variables of draining.

- Three flashlights with fresh batteries. Preferably waterproof or water resistant. It's a good idea to have at least your primary light be buoyant.

- Waterproof shoes or plastic bag liners. Remember, waterproof boots will also retain water. Thick shoes are nice because it can help prevent an animal from biting you, and you from stepping on any needles or other trash present in the drain. Also, a good grip is good to keep you from slipping.

- Drinking water for thirst. It's easy to become dehydrated in a drain. Be sure to keep your fluid intake up.

- Rations for hunger.

- Hydogen Peroxide or something to clean wounds with. You don't want to get a nasty cut down there and let the grimy water get into it. Clean your wounds and cover them, if you get any. Its cool if you put some gau

- A hat for spiderwebs.

- Cell phone. Reception is best at gutters. These can be handy at times, odds are they will be useless to you, except the one time you forget to bring one.

- At least one glove. These aren't really necessary, but its nice to have them handy. For instance, if there was an emergency and you needed to get out of the very last picture in this post.

- Knee pads. You never know when your going to wind up crawling. These won't take up too much room and are worth the space.

- Digital Camera - It's easy to forget your experience in a drain, and even what it looked like. Photographs preserve that. Digital cameras store many more pictures than film cameras, and developing is free. As a bonus, you can post them on the web without scanning. Unless you want to make a really big print a digital camera is probably superior for draining.

- Laser Pointer - These aren't absolutely necessary but you can use them to determine the length of tunnels, falls etc.

- Plastic Garbage bags. Good for storing items like the cell phone and also good for wading across deep water with.

- A small mirror mounted a wooden dowell. This tool may be able to see outside of manholes and determine if they are in roads or not. Never exit via manhole unless you have to.

- Identification and a small amount of cash. If you are caught by authorities, it's nice to have some identification to show who you are. Also after finishing a draining mission you may want to purchase some food or other items.

- To carry all this - a sturdy backpack that won't hurt your shoulders.


Gas: Dangerous gases can collect in drains where air ventilation is poor. Generally its not a problem in drains but more so in sanitary sewers. Often the gas's have no smell, or have smell for a little while then the smell vanish's. You need to be aware of how you are feeling, and if you start to feel the symptoms of bad air - get out.
For information on different types of gas and descriptions of them go here:

Flooding: People die in drains when they flood. If the water level begins to rise or sidepipes start gushing in water, get up to high ground or get out as quickly as possible - preferably the latter.

There are a few signs of flooding:
#1 Temperature change in water.
#2 Oily water.
#3 Increased sidepipe flow.
#4 Powerful gusts of wind.

A good rule to follow: No draining when its raining.
Read about Bob the Drainer:

CSO's: Combined Sewer Overflow. These are pipes that sanitary waste will exit through if the sanitary system becomes overloaded during wet weather periods. See sewage for more information on sanitary waste.

Sewage: Sometimes sewage flows, legally or illegally into drain systems. There are a variety of sickness's you can catch from sewage. Read about them here:

Wildlife: Rats, bats, crabs, racoons, skunks, fish - wildlife is very common in drains. If you SEE any wildlife, its best to back away and don't allow yourself to corner or threaten the animal. If an animal bites you, and you are confident you can catch it, catch it. If the animal has rabies you will need a vaccination immiedietly. It helps to make some noise by spashing as you explore, this lets the animals know you are there and they will retreat before you ever get the chance to see them.

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The Law: Draining is illegal in many areas. Make sure it's legal where you live, or have a good excuse prepared. Generally if you cooperate with authorities they won't arrest you. It's such an obscure hobby they might not even be aware of the of laws pertaining to them. It's also a good idea to carry only what you need. No drugs, alcohol, or aeresol products. Remember, "Public access to public works!"

Getting Lost: Here is one thing you probably don't have to worry about. There is generally a main tunnel with sidepipes connecting to it. The tunnel may split, but usually they reconnect after that. If they don't you'll still come to an outfall. Beware, if your city treats stormwater you might wind up in a treatment facility. If you are ever in doubt, turn back. Don't try to press on. Also, do not open manholes from the inside, unless you absolutely *must*, as they often lie in streets. The key is to be aware, and don't explore while under the influence of any substances. Remember, if you entered via an outfall the tunnel is just going to get smaller until you turn around. If your truthfully in doubt, follow the water. If you ever become trapped for whatever reason, calling people for help through a grille might not be a bad idea.

Bacterial Deposits: These are orange/red mush that collects in various areas of drains. It's comprised of minerals and bacteria, and is fairly common. If you got this in your face or swallowed it somehow, you may get sick. It's best to just avoid this stuff.

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To read an excellent guide to draining by the late Predator click here:

*All photos here have been taken by Kowalski.

See Also:
Storm Drain
Utility Tunnel
Steam Tunnel
Sanitary Sewer
Manhole Popper
Combined Sewer and Overflow (CSO)
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