Tuesday, August 8, 2023

Non-SI

This sentence stopped me in my tracks.

The reservoir at the dam adds 377,000 acre-feet of water to controlled storage on the Tennessee River system.

What on earth are acre-feet? Clearly it is a measurement of water. The standard Australia water measurement is Sydney Harbours, such as 'with a volume of water large enough to fill Sydney Harbour twice'. Everyone knows precisely how much water that is, give or take a high or low tide, even if they don't know any other water volume measurement. 

Non-SI sent me to Auntie Google. I had an idea it stood for International Standards and Fe-fi-fo-fum, I smell the the blood of a French madame and the initials are for a French term, Système International.

So SI indicates international standards. Non-SI means the measurement is not international standard but is recognised as being used.

Now, I think we do have a another measurement for large amounts of liquid aside from Sydney Harbours. I think it is cubic something. My memory is correct, it was once cubic feet and is now SI compliant cubic metres or litres, but that doesn't seem to be what is used here. We just use megalitres, and one cubic megalitre is 1,000 litres. Thank goodness. I understand litres. 

Victoria's Thomson Dam holds a multiple of Sydney Harbours at over one million megalitres. My photo taken in 2013.

Well, don't trouble yourself too much about this post, as I did some learnin'.

19 comments:

  1. This post has made my brain hurt. Thank you. I think.

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  2. A volume that is one foot deep and one acre wide? Lynn Marie

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  3. All about maths here. Maths is only a means to get to the course I want to do

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  4. Well, that is a lot of water. I feel no special urge to quantify it. That lack of curiosity has saved me many a headache. I feel as if I narrowly escaped one right now. 😊

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  5. I understand achy-feet but not acre-feet.

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  6. Use any measurement you want, just as long as the reservoir has enough sandbags.

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  7. I don't care so much about the measuring systems, I do care that Australia as a whole doesn't have nearly enough dams and pipelines. Queensland's annual flooding rainfalls would easily fill the dams and carry water to the drier states. I've said it before and I'l probably say it again at some future time. It bugs me.

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  8. Really!
    Interesting a body of water how they measure it.

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  9. That's given me a headache - can't cope!

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  10. Well there are 43,560 sq. feet in an acre, times one foot in depth. The number of sq. ft in an acre was on an exam I passed in 1978 - and I still know the answer.

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  11. Well I'm pretty clueless on megalitres and acre-feet:)

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  12. It's a lot of water. That's all I need to know!

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  13. thecontemplativecat here. I love your post. I grew up in Illinois, and heard of a REA dam being built in Tennessee, US. Hard to picture so much water/

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  14. The reservoir I go to kayak and swim is Foster Reservoir. I found this, on what it contains, in water, when full: 28,300 acre-feet (34,900,000 m3). I understand cubic feet or meters as a volume, can picture it, better than acre feet, that's for sure.

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  15. It's good to keep the brain cells working now and again.

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  16. I haven't heard of acre-feet. Here in India, the common method of expressing the volume of water in a reservoir is tmcft (thousand million cubic feet). Some people drop the ft, and says just tmc. One tmcft is 2,831 crore litres or in SI units, 28 million cubic metres.

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