h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Have been wondering what keeps water towers from freezing in northern parts of the world in winter. Any ideas?

Hello,

Well, a quick search through the Internet provides several possible answers (usually about large watertowers). Basically there isn't freezing because:

1. There is often a fair amount of movement and exchanging of water in the tower (either use or pumping), so it doesn't freeze in the same way rivers don't freeze.

2. Some water towers incorporate heating elements and/or insulation into their frames.

3. Some may also exchange water with a tank inside of heated water, thus moving and heating the water inside.

Yours,
Jake

It's probably the constant motion of the creatures that live in them ...ooo000OOO000ooo...ooo000OOO000ooo...

Or maybe it's the heat rising from the building below. Or maybe they're very well insulated. Or ... do you know, Jake?

Sal

Doh! Simulpost!

Ah well

Hello,

I'm not entirely sure in the case of New York City water towers (except that those creatures sure do make the water tasty), but I'm trying to visualize how the plumbing works for hot and cold water (is the water heater in the roof then?). I unfortunately live in a 6-story walkup, so we don't have a tower on the roof of our building, otherwise I'd just take a look there.

Yours,
Jake

I think some of those creatures may be the same as the ones you find in bottles of tequila. Now there's a substance that doesn't readily freeze in cold weather. Is that a clue? Well, maybe not ...

Perhaps you should investigate a tower on a neighbouring building, Jake. I've been trying to remember what we see in those movies where people are running around on the roofs of tall buildings. There are often little buildings perched on the big buildings, aren't there? Do you suppose the pumps and heaters might be stored in those structures, together with a man wearing overalls and carrying a bag of spanners?

Sal

Hello,

Actually in many cases, those little sheds store the machinery for an elevator, but who knows what else is in there? I live in the Village, and we don't have any buildings above 6 stories on my block, so I'd have to break and enter elsewhere to look up close. I don't think I can explain such things to the police as "research".

Yours,
Jake

Oh, all right then. It's hard, but we'll just have to wait till you can come by the information legally.

Sal

Wow! I've just noticed that my post number 3 has been whipped out by the moderators. What on earth did I say to cause that? I suggested that creatures moving in the water, insulation or rising heating might stop the water freezing. Good grief! How offensive could that have been?

Hello,

I think it was the spooky noises you made. They might have scared the small children around...

Yours,
Jake

Well, I thought the spooky noises were very amusing. And probably the right answer to the original question, too! Thanks for all your input!

The guy from the city tour told us that the water doesn't freeze because there are heating elements in every tower.

The primary reason for their existence is not supply of drinking water. The towers came into place because there's a city law which prescribes them for /every/ building higher than 6 (?) storeys as a firefighting resource!

Well, good showers and firefighting both rely on adequate water pressure, so they are required for buildings taller than 6 stories for both those reasons (who would want an apartment on the 18th floor with no water pressure).

Anyway, across the street from where I work they've been in the process of replacing a water tower on the roof, and it's rather fascinating. Right now, they've go one part of the wall up only. I imagine they'll complete the circle then put on the roof.

For those readers who happen to live in New York, this week's Time Out New York is a special issue all about New York's infrastructure (electricity, water, subways, etc). Apart from confirming many of the details of the article (always a relief), it had a few other interesting snippets and factoids:

1. Water towers are refilled as soon as they hit half capacity. A pump kicks in and they are filled up again. This is to ensure there's enough capacity for a fire, and can happen up to 20 times a day sometimes.

2. Water towers are emptied and inspected once a year for bacteria and cleaning. There are two main companies that build and test them.

3. Almost all the water in New York flows from a reservoir in Westchester county. This reservoir is 283 feet above sea level and much of the water pressure in New York for shorter buildings is from gravity and water's tendency to seek its own level.

4. In really large skyscrapers, the water tower is not on the roof. This is to keep people on the 3rd floor from being blasting with 60 stories worth of water pressure when they open a faucet.

5. From the time it falls into the farthest upstate reservoir until it trickles out a a tap, it takes six years for a drop of water to flow through the system.

All in all, pretty spiffy stuff. If you're in the New York area, go pick up a copy.

are you sure they said *6* years? If this true then why do they check the water for amoeba, bacteria etc in the facility? These results are worthless if the water spends years in the system!

Yeah, 6 years. It starts up in the top and feeds down through the reservoirs (imagine a large pipeline). You still do cleaning and checking, but most of the work is needed for when it's about to enter the giant tunnels that feed Manhattan. What's important is not the individual drops but the flow (in the same way, electrons don't move very far down a wire, but their combined movement makes electricity).

well, that makes sense