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Does stage tell you how much water is flowing in a stream?

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Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Let's get right to it, today's question is:

Does stage tell you how much water is flowing in a stream?

Not directly. You cannot say that because a stream rises from a 10-foot stage to a 20-foot stage that the amount of water flowing doubles. Think of a cereal bowl with a rounded bottom. Pour one inch of milk in it. It doesn't take much milk to make it up to the one inch level because the bowl is least wide near the bottom. Now, pour in milk until it is two inches deep -- it takes a lot more milk than it did to fill the first inch because the bowl gets wider as you go up. The same thing happens in a stream -- the stream banks will generally be narrower at the bottom and tend to widen as you go up the bank. So, the amount of water flowing in a stream might double when the stage rises from 1 to 2 feet of stage, but then it might quadruple when it goes from 3 to 4 feet.

Join us again tomorrow as we'll give you yet another new CoreFact. If you're interested in previous CoreFacts, or would like to check out CoreCast, our in-depth science podcast, browse over to If you would like to contact us here at the show or submit a question you think we should answer on the air, you can email us at or leave us a voicemail at 703-648-5600. Remember, long distance fees do apply.

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