New pond with bog plan - will this work do you think?


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Hello all,

I'm new to this forum but you all seem very knowledgeable and active. I'd love some advice.

I'm planning a new pond system to work over 2 levels of my backyard. I have an upper level where I plan to build the main pond, and then there is a rock wall, and then a lower level that's about 4 feet below. My plan is to have the main pond on the top level then a series of water spouts leading off the edge of the rock wall into a barrel bog filter and then into a large bowl with aquatic plants (and a pump).

The bog filter I am planning to setup will be a large wine barrel full of aquaponics clay balls to give loads of surface area for bacteria. I may put a layer of pea gravel in a basket hanging near the top of the barrel as well, to plant some plants in. I'm planning to put a tube next to the barrel (perhaps a wide piece of bamboo) with a pipe leading into the bottom of the barrel. The exit spout from the barrel is lower than the tube, so the water will flow from the tube, through the pipe into the bottom of the barrel, then up through the clay balls, and out the exit spout (in theory).

The water will then flow from the exit spout into a large pot or bowl which will have a pump in it. The pump will pump the water back up to the main pond where it will come out a bubble fountain on the far side, so water flows the full length of the pond. At the point where the bubble fountain comes up I am planning to setup another small bog, this time with pea gravel, that is in a separate container sitting at the surface of the main pond, so the water would top feed into the bog from the bubble fountain, and then travel through the pea gravel and out into the pond.

The water will then flow across the main pond, and pour out the spout into the feeder tube again... and the cycle continues.

I've included a drawing which will hopefully help explain it.

I will have to work out flowrates and what size pump to use of course, but is this a feasible idea? Or am I missing some massive flaw that will make it all fail?

Another question I have is, how do I connect an exit spout to the side of a pond made of pond liner? I don't want to make a hole in the liner for the spout to poke out, and I also don't want to have to use another pump to raise the water up to the top of the liner. A channel in the liner is the only option I can think of, but then how do I attach a tube to the end of the channel? Just with silicone sealant, then put a rock on top of it to hold it in place, or something like that? Seems a bit haphazard. Is there some trick to that sort of thing please?

Thank you kindly in advance for any advice you can give!
 
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One thing I have learned hanging out here - almost anything is possible!

Looking at your design, one thought comes to mind. Anytime you have water flowing from one level to another, the bottom most level has to be able to contain the full volume of water that will flow into it in case of power outage. So typically you would want your largest water volume to be the final level, not the first... unless of course you have some way to stop the water from flowing and are confident you will be around to make that happen in an emergency. The first seems doable. The second... not so much.

I'm also not so sure about all those tubes carrying water from one level to the next - you can use a pipe as an outlet, but a pipe as an inlet will get tricky. Just lining them up will be hard enough, but what if the inlet pipe gets clogged? I suppose you could install a filter before the outlet, but what if THAT gets clogged?

You can install a bulkhead through a liner and make a waterproof seal. We have one in our pond that has stayed tightly sealed for almost ten years now. You could, as you said, run the pipe over the liner and try to conceal it, but that's another design element that will make this a complex build.

Show us your space - maybe we can help work out some details!
 
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Thanks Lisak! Really appreciate the input. Awesome.

Regarding the issue with there being more water in the top level than the bottom, I hadn't considered that. However, I think it shouldn't be a major problem because the outlet spout from the top pond was likely to be pretty much on the surface (possibly with a pipe going down into the pond, to draw water from depth, but the actual outlet pipe right at the surface). So there would be a bit of additional water (a quarter inch of surface area perhaps) until the outlet level was above the surface of the main pond, but not the whole pond. Provided I leave a bit of extra space in the last pot in the chain to compensate for that then I should be OK in a power outage.

Regarding the inlet pipe, I assume you mean the inlet pipe for the bog filter barrel? I was under the impression that the preferred way to feed a bog filter was via an inlet pipe into the bog environment at the bottom of the bog? So it fills up slowly and then overflows slowly at an outlet near the top of the bog. Is that not the case? I'm not sure, I've never built one of these before.

Note that the inlet pipe in my plan goes all the way through the barrel and has a removable cap on the end. So if needed I can pop the cap off and either drain out any muck or shove a hose in and flush it out a bit.

I'm basing the bog design off this guys barrel bog:

What do you mean by a bulkhead? I'm a bit confused about that. Do you have a link to a picture or diagram you could show me?

It's night time here now, but I'll get some photos of the location tomorrow. Thanks again!
 
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What Lisa is referring to is a bulkhead fitting. Look it up. They come in various sizes to match your pipe diameter. They come with either threaded connections or glue-in connections. They are the best way to seal a through the wall inlet/outlet. The bulkhead fitting has two halves with a gasket. You drill your hole, screw the two halves together which makes a perfect seal. Now you can screw your pipes into the bulkhead fitting.

I'm not quite sure what you are trying to do or why. It seems a bit more complicated than it needs to be, but maybe I'm just not grasping the whole picture.

Most of us have our bog at a higher level than our pond. You have it the other around. Maybe that's what your property dictates, idk... maybe you have more room for the pond at the higher level.

The water level in my bog is slightly higher than my pond's water level. Water gets pumped from the pond to the manifold distribution pipes under the bog gravel. the water rises up through the gravel and flows back to the pond.

As a mention...if the pump stops for some reason, the bog holds its water. It's not going to empty out and overflow the pond.

I didn't want to penetrate any part of my liner. My pipe feeding the bog goes over the wall between the pond and bog. I stacked rocks around it to hide most of it.

All of my plumbing is within the pond/bog. If any leaks occur, it will just leak into the system. No water can escape out onto the ground.

This simple setup gives me absolutely crystal clear water. Previous to adding the bog I had constant solid green water. Now i can see clearly 3 feet down. My bog's surface area is slightly more than the suggested 30% of my pond's surface area.
 

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One thing I have learned hanging out here - almost anything is possible!

Looking at your design, one thought comes to mind. Anytime you have water flowing from one level to another, the bottom most level has to be able to contain the full volume of water that will flow into it in case of power outage. So typically you would want your largest water volume to be the final level, not the first... unless of course you have some way to stop the water from flowing and are confident you will be around to make that happen in an emergency. The first seems doable. The second... not so much.

I'm also not so sure about all those tubes carrying water from one level to the next - you can use a pipe as an outlet, but a pipe as an inlet will get tricky. Just lining them up will be hard enough, but what if the inlet pipe gets clogged? I suppose you could install a filter before the outlet, but what if THAT gets clogged?

You can install a bulkhead through a liner and make a waterproof seal. We have one in our pond that has stayed tightly sealed for almost ten years now. You could, as you said, run the pipe over the liner and try to conceal it, but that's another design element that will make this a complex build.

Show us your space - maybe we can help work out some details!
I agree with Lisa in that you may be inviting problems should you have a power outage in either direction. What if the top pond gets low and no longer feeds into your bog tube? Your pump will eventually starve and might die. Also, what you're doing is more a gravity feed bog, which is something I did for a while. It worked but I find 'forcing' the water via your pump works a lot better. When you let gravity do the work, what I found is that as the bog fills up with either roots or debris and clogs the media, that the water tends to backflow easier and then you have a surface bog instead of an upflow wetlands filter (which is the proper term for what you're doing--in nature, there is no force of water that pushes up through the 'bog' and then into a larger system, it more or less just free flows over the surface and that's why to be effective, you need a large surface area. In an upflow wetlands filter ((UWF)) you're using a vertical volume to do the same thing).

If you have room, I'd definitely reverse the positioning and place your barrel on top to let an overflow go back into your pond. You can bury the barrel if you want but it isn't necessary and would be easier to service if above ground. That said, I'd skip the barrel and just dig yourself a bog pond and have a lot less hassle all the way around. It isn't that your idea won't work but you are allowing a lot more variables to go wrong, imo.

Good luck whichever way you choose!
 
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I also agree that the big thing to consider is running out of water for the pump, the reason (as I think others have said) that you want the last body of water to be the largest is if the top pond loses a couple inches of water due to evaporation then you need enough water in the last container to be able to supply the volume water to the first pond needed to make it start overflowing into the 2nd and then have enough to fill that up to have it flow into last container to continue the cycle. If you have a 1m by 1m 1st pond and its 1inch low you would need 25.4 Litres to be pumped into it from the last container.
 
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This design i do not believe will work for long. As the bog ages and gets to where it starts doing its job . The roots from the wetland plants and the clogging of the gravel will then require more pressure to get the water to pass through the bog. Now if you had your feed at the bottom of the upper pond similar to main drain you'd get the head pressure possibly to keep the water flowing and not backing up that pipe. But the creates other issues to say the least. I'm not sure why you want the bog as drawn but change the order pump to the bottom of the bog. And let it gravity feed to the pond all done. I tried a similar experiment but it was using an aqua block as a base for an island and I planted papyrus . So the roots were basically hanging in open water. Within one season those grew to such an extent that when I went to break it down the root mass was thicker then a brillo pad. There's a picture of it in my pond build. I can't see and gravity feed lasting for too long
2727.jpeg
 
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Now could you do a small amount of water constantly dripping into the tube so you equaling what the bog will allow to drain through . That should work just fine I have what I call a stagnant bog theres no flow through the bog its just plants sitting on the side of the pond in about a inch of water that saturates the soils . Great home for pitcher plants.
Great drawing by the way very clear as to your intent .
 
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@Pharian - the guy in the video you posted used a bulkhead. He referred to it as a uni-seal.

I didn't watch his whole video - it was kind of hard to watch actually, with all of his shots being so up close. Also made it kind of hard to understand what he was doing, unless you are already familiar with the concept of a bog filter.

I'm a little confused about his construction - it appears the water both enters and leaves the bog from near the bottom, unless I missed something. The standard construction of a man-made wetland filter will have the water entering the bottom of the bog, passing through the manifold and being pushed up through the layers of rock, gravel and plants and then leaving the bog at the top, most usually via a waterfall, but some do use a pipe for an outlet. Having the water flow through from back to front just at the bottom doesn't make much sense to me. Again - maybe I missed something.

There are better videos to explain the process of building a free-standing bog filter. Here's one that I always recommend:


The Pond Digger is a great resource - his content is top notch and he's been constructing ponds for a living for a long time. He's one of the few pros who really went all in on making step-by-step DIY videos for the homeowner who wants to build their own pond. You can learn a lot from all the other content creators out there, but Eric really breaks it down to each step.
 
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Awesome guys. Glad I came here before I started building! Really appreciate it.

I think I’ll give up on the idea of incorporating a lower and upper level to the same pond system and build one larger pond and bog filter on the upper level, and then setup a few containers that flow into each other to fill with plants on the lower level.

I’ll check out those videos about the bog filter too.
Thanks again!
 
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