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 Post subject: Did you know?
PostPosted: October 4th, 2009, 10:29 am 
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"The mechanical work of a river is much greater than the chemical, and is dependent upon the velocity of the current, varying directly as the square of that velocity. The velocity of a stream is the rather complex resultant of several factors, the chief of which is gravity; the steeper the slope of the bed, the swifter the flow of water. A second factor is the volume of water, the velocity varying as the cube root of the volume.
That is to say, if one of two streams which flow down the same slope has eight times as much water as the other, it will flow twice as fast. Other factors enter into the result, but slope of bed and volume of water are much the most important."

The A B C of Geology
by Allison Hardy.

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 10:43 am 
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...note to self, trouble sleeping - read Hardy, zzzzzzz

:)

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 10:51 am 
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Hey I think I'll invite Allison to a party. There is sure to be some spirited discussion around this........ :rofl:

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 11:00 am 
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When water volume in the stream drops, the slower-flowing boundary layer that exists over the stream bed, next to sand, pebbles and boulders, occupies a greater proportion of the total stream volume and velocity drops... the boundary layer flows more slowly over a rough stream bed, while the water above the boundary layer flows more quickly because rocks and other materials in the stream bed are not slowing it down.

At some point very close to the stream bed, the effect of the boundary layer slows the water velocity down to near zero... this is where fish and invertebrates can relax and take refuge from currents especially if the stream bed is rough... oops, channeling Fluvial Ecology 331 there for a moment.

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 12:38 pm 
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Good stuff to know. Firms up squishy beliefs we held already.


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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 1:32 pm 
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Quote:
Other factors enter into the result, but slope of bed and volume of water are much the most important."


:thumbup:

In otherwords shit flows down hill. fascinating.

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 1:51 pm 
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Quote:
In other words shit flows down hill.


This only applies to urban rivers.

:o

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 2:23 pm 
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Not only that, but the more there is, the faster it comes! Or is it the faster it goes? At any rate, the more there is, the more there is to come!

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 Post subject: Re: Did you know?
PostPosted: October 4th, 2009, 4:13 pm 
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Dan. wrote:
Quote:
Other factors enter into the result, but slope of bed and volume of water are much the most important."


:thumbup:

In otherwords shit flows down hill. fascinating.


Still, it's sweet to know that if only 1 ton of shit were coming down Yonge Street on a rainy October afternoon, you could skip across in your new suede shoes, but if the lift station had blown a pump you'd have to hustle.

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 Post subject: Re: Did you know?
PostPosted: October 5th, 2009, 8:01 am 
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frozentripper wrote:
Quote:
In other words shit flows down hill.


This only applies to urban rivers.

:o


Now that is something I did not know.... What direction does it flow in rural areas?

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