I want to create a bog to clarify pond water

by Harry David
(Bloomfield, CT 06002)

I have two koi ponds with two separate waterfalls. I am trying to minimize UV lights, bacterial agents etc that is necessary to clarify the water especially in the summer. I want to build a bog fed by a pump through the waterfall in order to clarify the water. Thoughts?

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Doug says - if I remember my engineering data correctly, the rough way to calculate the size of the bog necessary to handle all pond filtration so you don't need any other system is to calculate the square footage of the ponds and equal that in bog space. If you have 1000 square feet of pond surface, you'll require 1000 square feet of natural bog.

The issue here is one of maintenance. A small bio-filter is doing the job of a bog but in a concentrated form. But you have to maintain it regularly to pick out leaves etc. And the filter size and flow rate of water through the bio-filter has to be matched to the size of the pond.

If you want a natural bog - one where you don't have to clean it out - and handle the same flow rate - then you have to go bigger than the plastic ones. And you have to design your outflow from the pond to fill the bog equally and not carve a channel through the bog to create a stream. Smaller bogs can be built but then you run the risk of having to clean them out if they go "bad" and start to smell like a sewage tank. Or they don't have the capacity to fully clean your pond and you wind up needing a bio-filter etc anyway.

The short answer is that you create a second pond area "uphill" from your current ponds (remember water flows downhill so the bog exit has to be slightly above the upper pond)

The bog is half substrate (pea-gravel) on the bottom and half peat-based soils (I used straight peat on mine) on top.

That's the rough stuff you need to know in order to start planning - do you have the size of garden to handle the size of bog needed

Can you design the bog so it encircles the pond and not just another blob somewhere?

But start with fitting in the square footage.

Hope that helps a bit

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I want to create a bog to clarify pond water

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Mar 09, 2011

dreaming of his garden in winter
by: Doug

Great questions all! I'm going to have to answer these for sure and I've put them on my to-write list for individual articles. I really can't answer them all here in this simple form - sorry. But they did hit my writing list and I've moved them to the top of the pile for this site.

Mar 07, 2011

I want to create a bog to clarify pond water
by: Anonymous

Thanks for both responses. I may design the bog to be upstream from the two ponds and perhaps add some aeration there as well.

I like the idea of feeding the pond from the bottom via perforated PVC pipe -- I suppose this maximizes aeration and avoids putrefaction?

I was considering having the waterfall draw water from the big pond and having it's outflow feed into the bog. But I am now wondering if it is not better to feed the bog from below via a small pump that draws water from the big pond and then having the bog flow over a waterfall back into the pond.

So pond area is the determining factor? Not volume? My proposed bog area is mostly in shade? Is that preferable to sunshine?

What about a bottom drain for clearing out the pond occasionally?

So peat moss is best for lining the bottom of the bog?

Does it make sense to fashion a bacterial filter en-route to or from the bog? I have the area. And what kind of flow rate through the bog is adequate?

Any book I can study prior to construction? I do not mind buying a bio filter if they are effective.

Appreciate the advice.

Harry

Mar 03, 2011

Veggie Filter also known as a Boggarden
by: gaucho10

Go to my Photoshop page and take a look at my "Pond Construction" project at the end of this post. I have been working on my ponds for about 6 years now and I think they are finally done. The bog garden really works but like Doug said, you might have to clean it once in a while. I do not get any foul odors because the water is fed from underneath the crushed stone through perforated PVC pipes. The water then rises to the surface and flows over a small waterfall into another small (mini) pond, then into the main pond. I have had this veggie filter going for a few years now and so far it don't smell. The plants that are growing there are perennials, mostly cattails and water lilies. I do have other plants growing there which I did not plant but they grow like crazy. A wildlife biologist came over to inspect my ponds several years ago before completed and he stated that my small pond would become a good place for amphibians and dragon flies. It really did happened as he said and now I have all sorts of reptiles and amphibians living in and around the small pond. The large pond contains no gravel, very few summer tropical plants, some frogs and 10 large koi. I usually have to take out the baby painted and snapping turtles that fall into the pond. I think that they get attracted to the pond by the waterfall noise (sound).

I hope this helps

http://s30.photobucket.com/albums/c319/Gaucho101/Pond%20Construction/

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