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Thread: HenryC's Pond Construction

  1. #211
    Daihonmei MikeM's Avatar
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    Bumped up for Yamato.

  2. #212
    Tategoi Yamato's Avatar
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    Sorry, I am going to bother U with lots of questions... but I am building a pond too, and here I have no one to advise me...Mike suggested that I have a look at your design.
    -I dont know much so please be patient with me. Newbie here that is building a second pond within 1 year and dont want to get it wrong again.
    First what is your consideration on this type of flow? I found here in this PDF that a pond with ratio, W:L higher than 1.45, is less efficient when the debris are swept in a circular fashion...
    Maybe what they wrote is wrong or maybe U included some considerations, to improve it?
    Link:http://elmu.umm.ac.id/file.php/1/jur...c2000/1159.pdf
    Can U explain it please.
    Another type of pond design I see promoted of late, is river/stream flow...
    I found some publications that state that that kind of pond needs 30-35% more turnover in order to fave the floor swept well.
    I personally dont see any advantages in that type of design, apart from the fact I have seen some people talking about, their Koi bending????
    For me economy is an important factor not only when building but maintenance wise too.
    I am still in the planning stages so your advise will be appreciated.

  3. #213
    Tategoi Yamato's Avatar
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    After reading the thread, I have some more questions:

    Air domes: How are they positioned ? They look like BD to me and maybe U put them between the BD on the same line?
    I don’t understand what is their purpose and why they are at that position.
    I saw somewhere (not sure how good that info is) that there is a dead zone created above the BD and that is the main reason for the aerated BD…????? To improve the circulation above the BD, and mix the water above it.
    Some people claim that BD's air dome sucks/ pushes water upwards. If that is true, how will that help the circulation in this pond?
    I can see U have massive flow, but why are the airpits where they are?

    BD: is your BD going to suck water, mainly from the vertical column above it?

  4. #214
    Nisai
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    Hi Yamato,

    Air Domes........... The reason that they look like BDs to you, is because they ARE bottom drains, but with an air bladder fixed on to the drains top. The reason that they are popular is that as well as providing the necessary airation to the pond, they are brilliant at sweeping the pond floor clean of any debris.

    How they work......... The air bladder fixed to the drain cover comes with hundreds of tiny holes in it, which in turn, when the air is turned on, sends thousands and thousands of tiny air bubbles in a column upwards to the pond surface. From there, the air/water mix is pushed outwards towards the pond edges, down to the floor, and then circulates back to the bottom drain, thus sweeping the pond floor.

    Hope this helps

    Chris

  5. #215
    Tategoi Yamato's Avatar
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    Quote Originally Posted by ageinghippy View Post
    Hi Yamato,

    Air Domes........... The reason that they look like BDs to you, is because they ARE bottom drains, but with an air bladder fixed on to the drains top. The reason that they are popular is that as well as providing the necessary airation to the pond, they are brilliant at sweeping the pond floor clean of any debris.

    How they work......... The air bladder fixed to the drain cover comes with hundreds of tiny holes in it, which in turn, when the air is turned on, sends thousands and thousands of tiny air bubbles in a column upwards to the pond surface. From there, the air/water mix is pushed outwards towards the pond edges, down to the floor, and then circulates back to the bottom drain, thus sweeping the pond floor.

    Hope this helps

    Chris
    OK! Thanks! That much I know, but What I dont get is how does the BD work in that position? I suppose for them to put it there it must be better.... But what makes it better?
    If U look at the diagram, there are opposing flows here that dont compliment/assist each other.
    What I have seen is the active suction from the BD is not much around the BD. The debris are mostly swept by the current in the the pond created by the jets. The velocity with which BD sucks is reduced at a distance not more than 20"???(not to sure) (depends on many factors but it is not much)(red dotted area)
    Now due to the fact that width to length ratio of this pond is greater than 1.5 times, the sweeping ability of the current in the pond is reduced as opposed to if he had 2 or 3 circles of flow in the pond.
    What criteria did they use to build the flow like that?
    Do the bottom drains and air pits being where they are make any difference and how?
    I tried to draw it to see how it operates, but I am not getting it.
    Attached Thumbnails Attached Thumbnails HenryC's Pond Construction-bd-kb.jpg  

  6. #216
    Jumbo HenryC's Avatar
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    I was not able to view the PDF but I am guessing that it did not take into consideration the impact the air columns have on the pond's water circulation. My bottom drains are different, but regular aerated bottom drains have an air dome on top of the bottom drain. This upwardly moving air column pulls water up, which creates a circular motion perpendicular to the water flow created by the water returns. The water flows up, then out to the pond sides, down the pond walls then across the pond bottom sweeping debris to the bottom drains. On my first pond (rectangular in shape), I started with non-aerated bottom drains. The corners of the pond would build up debris. When I converted the bottom drains adding aeration to the top, the resulting perpendicular circulation swept that debris out of the corners and to the bottom drains.

    On the new pond, I went with a custom type of aeration that allowed for no protrusions extending from the pond bottom. The aerators on the new pond are not part of the bottom drains but instead placed inbetween the bottom drains. They create the same perpendicular circulation. When the aerators are on, the water circulation completely changes. My pond floor is almost always debris free.

    Quote Originally Posted by Yamato View Post
    Sorry, I am going to bother U with lots of questions... but I am building a pond too, and here I have no one to advise me...Mike suggested that I have a look at your design.
    -I dont know much so please be patient with me. Newbie here that is building a second pond within 1 year and dont want to get it wrong again.
    First what is your consideration on this type of flow? I found here in this PDF that a pond with ratio, W:L higher than 1.45, is less efficient when the debris are swept in a circular fashion...
    Maybe what they wrote is wrong or maybe U included some considerations, to improve it?
    Link:http://elmu.umm.ac.id/file.php/1/jur...c2000/1159.pdf
    Can U explain it please.
    Another type of pond design I see promoted of late, is river/stream flow...
    I found some publications that state that that kind of pond needs 30-35% more turnover in order to fave the floor swept well.
    I personally dont see any advantages in that type of design, apart from the fact I have seen some people talking about, their Koi bending????
    For me economy is an important factor not only when building but maintenance wise too.
    I am still in the planning stages so your advise will be appreciated.
    Henry

    Orlando, FL

  7. #217
    Tategoi Yamato's Avatar
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    Quote Originally Posted by HenryC View Post
    I was not able to view the PDF but I am guessing that it did not take into consideration the impact the air columns have on the pond's water circulation. My bottom drains are different, but regular aerated bottom drains have an air dome on top of the bottom drain. This upwardly moving air column pulls water up, which creates a circular motion perpendicular to the water flow created by the water returns. The water flows up, then out to the pond sides, down the pond walls then across the pond bottom sweeping debris to the bottom drains. On my first pond (rectangular in shape), I started with non-aerated bottom drains. The corners of the pond would build up debris. When I converted the bottom drains adding aeration to the top, the resulting perpendicular circulation swept that debris out of the corners and to the bottom drains.

    On the new pond, I went with a custom type of aeration that allowed for no protrusions extending from the pond bottom. The aerators on the new pond are not part of the bottom drains but instead placed inbetween the bottom drains. They create the same perpendicular circulation. When the aerators are on, the water circulation completely changes. My pond floor is almost always debris free.
    Thanks for the explanation.
    What I am concluding here isnot necessarily right)
    -Since U have massive turn over rates, Your pond relies on the water flow created by the jets on the walls entirely to sweep dirt to the BD's
    -U dont have too much dead area(stagnant) above the BD since the drain exerts some pull in that area though not too high, since your pond is deep and the velocity of the suction force diminishes greatly above the drains.
    -I agree with U that that is how the air dome operates..., but in your case I see a bit of a conflict at the base of the air dome , half way between the BD and air dome: They are both pulling in different directions the water. It is good that your air outlet is higher than the bottom drains...not much chance of debris accumulating there, since if there were any debris there the air domes were going to suck and lift it up.. But are your air domes not destructing the flow towards the BD's? In a conventional aerated BD they compliment each other.. No? (since they both pull in the same direction along the flow...)
    That is what I am trying to understand...Did another drawing of how the flows might be...but still the flows created by the BD and air are not clear to me in this particular case... maybe I dont all the things governing the flows????

  8. #218
    Daihonmei MikeM's Avatar
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    I think Henry was explaining that it is the upward movement of water caused by the aeration, which then sweeps downward when it reaches the pond wall, that does the most in moving debris to the drains. The returns also keep debris from settling, but are not as effective in moving debris toward the drain as occurs with aeration. Henry's design might not be quite as efficient (in theory) as would be the case with aerated bottom drain domes, but he succeeded in having no protrusions from the floor on which a fish might injure itself. A bit of a compromise to meet two goals.... but, in actual practice, his pond's floor is always clean.

    My pond uses domes, but it is much wider than Henry's, and not as deep. Debris has further to go, so some debris will be seen from time to time. In a pond that is 10-12 feet wide, debris is swept toward the drains more quickly.

  9. #219
    MCA
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    Honmei MCA's Avatar
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    I would suggest studing the koi pond construction topics on the excellent Welch site: A Guide to Modern Koi Pond Construction.

    The site gives excellent advice on pond shapes, depths, gravity feed filters, installation of bottom drains with air domes...etc.

  10. #220
    Tategoi Yamato's Avatar
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    Quote Originally Posted by MikeM View Post
    I think Henry was explaining that it is the upward movement of water caused by the aeration, which then sweeps downward when it reaches the pond wall, that does the most in moving debris to the drains. The returns also keep debris from settling, but are not as effective in moving debris toward the drain as occurs with aeration. Henry's design might not be quite as efficient (in theory) as would be the case with aerated bottom drain domes, but he succeeded in having no protrusions from the floor on which a fish might injure itself. A bit of a compromise to meet two goals.... but, in actual practice, his pond's floor is always clean.

    My pond uses domes, but it is much wider than Henry's, and not as deep. Debris has further to go, so some debris will be seen from time to time. In a pond that is 10-12 feet wide, debris is swept toward the drains more quickly.
    Thanks Mike!
    That is what is worrying me. Is 12" not to great of a distance between BD and wall of pond.
    Since I want to be a bit economical (within reason) with my flow rates, that was a thing that was bothering me.
    What is the distance between your BD and wall, flow rate through the BD..?
    In short I want to know the minimum flow through a BD in order to keep it clean.

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