# Water Volume of 30 inch culvert??

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• posted on April 17, 2005, 3:19 am

Can anyone calculate the number of gallons that a 30 inch wide culvert, 48 inches long, will hold ??
Thanks for any info !!! --James--
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• posted on April 17, 2005, 1:07 am
Charlie Bress wrote:

You're also assuming a round culvert.
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• posted on April 17, 2005, 3:40 am
146.88 (assuming the 30 inches is an inside diameter)

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• posted on April 17, 2005, 5:42 am
James wrote:

culvert, 48

"Can anyone calculate the number of gallons that a 30 inch wide culvert, 48 inches long, will hold ?? "
Pie are square
Area of a circle equals Pi times the radius squared.
3.14 * 15" * 15"
33912 cuin 33912 cubic inch = 146.8051948 gallon [US, liquid]
This assumes the culvert is round, is capped on one end, and stood up, then filled to the rim.
A culvert, laid horizontally, in the ground, would be filled to about 85% to 95%, considering air would be at the top. Well, that would be during a flood, but in dry times, there might be a few inches, flowing.
Is the culvert oval shaped? I'll assume round.
Is the water stagnant or flowing?
Since you are too lazy to do your homework here's a bonus question.
What if you have a drainage canal, 15 feet wide and 10 feet deep. Water is flowing, and the depth is 2 feet on the wall markings. You look upstream to the mountains and it is raining steady. You have 3-30 inch diameter x 20 foot culverts, side by side, in the culvert and they are covered in concrete, with a road over them. Height from stream bottom to road is 5 feet. You have someone 100 feet upstream, drop a floating object in the water, and it takes 10 seconds to reach you.
How many gallons per minute are flowing through the culverts?
At what flow rate will the flow of water, exceed the capacity of the culverts, and flow over the top of the road: by 1 inch? by 12 inches? by 48 inches?
:)
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• posted on April 17, 2005, 5:44 am
Edwin Pawlowski wrote:

It seems like an odd question to ask about a culvert. Maybe the OP wanted something along the lines of flow rate (gpm)??
-
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• posted on April 17, 2005, 6:20 am

Probably anticipates using it for a tank/reservoir.
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• posted on April 17, 2005, 8:02 am
Bravo!!!
Now, what did you win?
That much in free gasoline?

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• posted on April 17, 2005, 9:14 am

The fact that this was posted to six newsgroups is a sad commentary on the math curriculum of our schools.
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• posted on April 17, 2005, 6:41 pm
doubter wrote:

Unless the cylinder is up-ended and set in concrete, or otherwise made water-tight.
CC
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• posted on April 17, 2005, 7:05 pm
No one bothered to tell James how to convert cubic inches to gallons. The conversion is 7.47 times cubic feet. So it was easiest to convert inches to feet before finding volume - area of the base times height. I don't think you can blame good education on not knowing that conversion rate. Carolyn

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• posted on April 17, 2005, 10:04 pm
doubter wrote:

Or a water tank or concrete form on the cheap.
CC
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• posted on April 17, 2005, 11:10 pm
wrote:

Unless a horizonal boring tool is used underground to provide a complete cylinder, the above needs to be divided by 2.

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• posted on April 18, 2005, 12:24 am

48
The answer is zero. With only 2 dimensions, you have a flat surface ;) Frank
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• posted on April 18, 2005, 1:24 am
Carolyn LeCrone wrote:

Sure you can and should. An education isn't supposed to just stuff you full of facts, it is supposed to each you how to learn. In this day and age it is pretty easy to look up any unit conversion that is needed and there are many online utilities that will even perform the conversions for you.
Matt
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• posted on April 18, 2005, 1:25 am

Which would be a strange culvert indeed.
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• posted on April 18, 2005, 1:31 am

Bull crap. It was taught in freshman science, but if you forget, I have at least three books with that information. Education is not just knowing facts, but how to find answers. Posting such a simple question on six newsgroups is just a waste of time when it can be found so easily even with a Google search. You have to want to know and not just take a lazy way out.
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• posted on April 18, 2005, 10:07 am
Halcitron wrote:

Better: "How much water flows out of the mouth of the Mississippi per year. Give two methods:
Answer 1: Assume width of river at the mouth is two miles, flow is 5MPH and average depth is five feet. Turn crank.
Answer 2. Assume Mississippi drains the center half of the country (from Rockies to Appalachia). That is, 1500 miles E-W, and 1000 miles N-S. Further assume this area gets 50" of rainfall per year. Turn crank.
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• posted on April 19, 2005, 6:04 am

I was thinking the same thing.
If you assume the width of the culvert (that's assumed to be round in shape) is also 2 times the depth (assuming a half-circle culvert), then you could get that too.
I agree, not enough information given. I propose a new culvert shape with straight sides of uneven length, with a bottom made of various balls placed under a huge pool liner.
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• posted on April 19, 2005, 4:55 pm
Frank Logullo wrote:

A cylinder only *has* 2 dimensions...
The fact the OP gave only 2 dimensions makes the assumption of a cylinder appropriate.
oh, I almost forgot... ;)
AL