Evaporation and heat loss of your pond

Discussion in 'Water Chemistry' started by MitchM, Jun 5, 2017.

  1. MitchM

    MitchM

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    I agree.
    I was hoping that by running through some computations, we could appreciate the forces at play that contribute towards evaporation and heat loss, instead of wondering if they have a leak or buying pond heaters thinking the heater is accomplishing something that it's not.
     
    MitchM, Jun 6, 2017
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  2. MitchM

    Meyer Jordan Tadpole

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    I would venture to guess that no more than 0.1% of the ongoing processes in a pond are visible to the naked eye, but control 99.9% of the visible results.
     
    Meyer Jordan, Jun 6, 2017
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  3. MitchM

    Jimmy Gibson

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    I have seen the water temperature as high as 84 on a really hot day ( we have already hit 90 some days) and on those days early morning about 79 degrees, but on normal springtime days maybe 80 late afternoon and 77 to 78 in the morning......
     
    Jimmy Gibson, Jun 6, 2017
    #23
  4. MitchM

    Jimmy Gibson

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    Also something to add to this...... My filter and pump are over 100' from my pond, I have a 2" line from the skimmer a 2" line from my bottom drain going to the suction side of my pump and a 2" line from my filter to my waterfall.... And they are buried 18" in the ground...... Why I am saying this I noticed this last winter my pond would cool down with the ambient temperature and due to the fact of a vigorous waterfall but it would warm up quickly and I thought that was due to the piping being in the warmer ground..... Not intentionally trying to muddy the water but just wondering
     
    Jimmy Gibson, Jun 6, 2017
    #24
  5. MitchM

    Meyer Jordan Tadpole

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    Certainly a factor.
     
    Meyer Jordan, Jun 7, 2017
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  6. MitchM

    sissy sissy

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    Reson I like having my hose in the pond and if it ever leaks it goes into he pond and not in the ground
     
    sissy, Jun 7, 2017
    #26
  7. MitchM

    MitchM

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    1 inch of water loss in your pond is about 177 gallons.
    With the conditions you posted, I came up with a wide variation, between 5 and 15 gallons per day loss calculated.
    Different wind speed, air and water temperatures can make a big difference.
    Aeration is also a factor to take into consideration, and I found this paper on the effects of evaporation on a pond.
    https://research-repository.griffith.edu.au/bitstream/handle/10072/46754/78054_1.pdf;sequence=1
    I haven't gone through the paper yet.
    I'm sure a waterfall and/or stream design will also increase evaporation.

    Using the pan evaporation rate for your state for the month of June, you should be losing only about 45 gallons per day. I found monthly pan evaporation rates here:
    http://large.stanford.edu/courses/2010/ph240/harting2/docs/NWS34EvapTables.pdf

    I'll have to go through the original paper I posted for this thread and have a look at what the water body was that they used for the study. I imagine it was a still pond.

    Thanks
     
    MitchM, Jun 7, 2017
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  8. MitchM

    Gordo33

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    Nope:(
    This the line that is confusing me: Wp=.097+(.285x-.034)x899
    Why is your result for (Pw-Pa) - .034 multiplied with the velocity result .285 before adding 0.97 to .285 as shown in the formula (0.97 + .038v). It's been a long time since I have had to deal with math formulas but I thought you complete the work inside each bracket before performing the other functions.

    I thought it should be
    (.097+.285) x (-.034) x 899
    (.382)x(-.034) x 899

    I was trying to figure out my ponds evaporation rate and ended with a negative number as I would using your numbers as discribed above.
    Straighten me out what am I missing here?

    My ponds numbers are
    Air temp 92 f
    Wind velocity 7 mph
    Pond is 200 sf

    Thanks
     
    Gordo33, Jul 21, 2017
    #28
  9. MitchM

    Meyer Jordan Tadpole

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    While this may be useful for historical meteorological data. It is hardly useful for current conditions.
    This data is for a period of 1964 - 1982 and as such is 35 years old. Much has happened with climate in the last 35 years.
    If I were to rely on what current data is available I would refer to-
    https://www.usda.gov/oce/weather/pubs/Weekly/Wwcb/
    Though current, even this is may not be much help as many of the pan evaporation stations have been closed in the past 35 years thanks to modern technology.
     
    Meyer Jordan, Jul 21, 2017
    #29
  10. MitchM

    MitchM

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    To complete the equation for your pond, we also need the water temperature.
    What is that number?
     
    MitchM, Jul 22, 2017
    #30
  11. MitchM

    Gordo33

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    79 degrees F
     
    Gordo33, Jul 24, 2017
    #31
  12. MitchM

    MitchM

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    Sorry Gordo33, I got tied up with work.
    I believe if you come up with a negative number from the Pw-Pa equation, at that point in time there is no evaporation occurring.
    Once the air temperature drops down below 80F, you will have a positive number and evaporation will start to occur with a water temperature of 79F.

    I may have made a mistake with my original calculations, I'll have to go over them again. Thanks for pointing that out.
     
    Last edited: Jul 29, 2017
    MitchM, Jul 29, 2017
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  13. MitchM

    RichardSJPonds

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    RichardSJPonds, Aug 15, 2017
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  14. MitchM

    Meyer Jordan Tadpole

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    Meyer Jordan, Aug 15, 2017
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  15. MitchM

    MitchM

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    uh-oh....
     
    MitchM, Aug 16, 2017
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  16. MitchM

    RichardSJPonds

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    TBH, we don't include IonGens in our regular ecosystem ponds, too easy for people to overdose the copper and kill everything. They're more like a last resort when gentler treatments aren't doing the trick. There are ponds that do well with one, they tend to be larger ponds with a recurring pea soup water problem.
     
    RichardSJPonds, Sep 5, 2017
    #36
  17. MitchM

    Meyer Jordan Tadpole

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    Sadly, this is the prevailing mind-set of this hobby...that Pond Treatments are necessary, completely normal and.....safe. A belief that is easily dispelled with a little patience and prudent husbandry. Work with a pond, not against it!
     
    Meyer Jordan, Sep 6, 2017
    #37
  18. MitchM

    Mike in Vermont

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    I don't have a liner. The bank will absorb water. Quite a bit if it's real dry.
     
    Mike in Vermont, Sep 6, 2017
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