Operation Duck pond is a go! Phase 1: pre-planning

[nimrod]

Okay guys, this is my first post, but I've been lurking, and absorbing information like a madman. The time has come for me to build a pond. But I need some help from y'all experts. I'll list my requirements, and my planned features, then ask some questions about my overall strategy as well as some specifics about bits and bobs. Let's start with the plan:

Circular pond - 12ft diameter
depth: 3ft preferred
critters: 4 ducks (poop machines)
Filtration: BOG/wetland.
water feature: small fall from bog back into pond.

Rough plan: The idea is that the circular pond will be 60% pond, and 40% bog, I'm prepared to go up to 50% bog. The bog will be raised above the pool to facilitate a return of clean water back into the pond.

Picture:

Questions:

1. Will a 40% bog be enough to filter out all my duck’s waste? These guys poop a lot!
2. Most of the builds I have been looking at have a pump that sits off the floor of the pond, or in a skimmer box/negative edge… What happens to all the sludge that collects on the floor of the pool?
3. Should I use some sort of solids filter (radial flow, or swirl)? My preference is obviously not to have yet another filter in addition to the bog. Do you use a second pump for that, or can I split the flow? It is my understanding that the key to a good solids filter is retention time, so if I would need to slow the flow down somehow?
4. Do I need a skimmer?
5. The barrier wall between bog and pond… what’s the best way to build this? Under the liner with cinder blocks? Just dig out the two halves of the circular plan?

I have about 50 more questions, but I’ll leave it at that. Thank you all!

 

[addy1]

Welcome to our forum!

I draw from about a foot off the bottom, just fish, even 10 years later I do not have much muck on the bottom, without cleaning. You could, every now and then, stir it up let floating debris get sucked into the bog. My pump is external, my preference, have never like submersibles.

I have a lot of fish, no count but over 100, the water stays perfect with only my bog.

I do have a skimmer, mainly because I had two apple trees dropping flowers, maple tree dropping seeds. Maple tree now dead, apple trees cut back. Very little gets pulled into the skimmer.

 

[nimrod]

Thanks Addy,
I knew when I put the word "bog" in my post I'd be getting a visit from you. At this point, I think you are the official bog-filtration representative. I love the simplicity of just using an oversized bog, and no other filter.

So you pull water into your pump from the main pond, not from the inside of your skimmer?

 

[addy1]

So you pull water into your pump from the main pond, not from the inside of your skimmer?

lol I have a simple bog, others here have built fancy ones..................... mine is liner, pvc pipes, pea gravel, plants

I use a external pump, most of the water is pulled from the big pond. I have a T between that pull and the skimmer pull. I keep the skimmer pull on low, it just adds circulation. If I pulled all the water from the skimmer it would be too hard of a pull. My pump is about 6800 gph, without counting head factors.

I built mine with the bog separate from the pond, all one liner. Built a landscape timber wall between the two, covered the wall with the liner. We have a 3 foot or so opening for the water fall back into the pond over a flat rock. Over time the bog water weeps over the entire wall into the pond. I have had no issues except excess plant growth that can redirect water flow.

It is probably 1/3 the size of my pond. Surface area maybe 1/4 , it is deep 2.5 feet, wide 4.5 feet or so, long 26 feet or so. Works great. I can turn on the pond in the spring and ignore it all summer, except pulling excessive plant growth.

 

[addy1]

I turn all off in the winter, due to the external pump. Within a few days of turning it back on it is back to clear water and stays clear all summer.

 

[JamieB]

Considering how ducks , you may want to be flexible on your plumbing plans. Start with what you want, but plan for setting up a solids filter, just in case. Also, pick bog plants with the ducks in mind. You’ll want some that they won’t stomp flat, or eat up. Expect ducks to enjoy the bog half too.

 

[brokensword]

a bog is not a mechanical filter, so I'd not introduce any solids; clogging can happen, especially this way. Meyer Jordan advocated a bog prefilter when I had clogging. Since, I've raised my pump off the bottom and ditched the prefilter, but when I was doing such, I did catch a lot of crud I thought could indeed clog.

 

[j.w]

@nimrod

 

[nimrod]

a bog is not a mechanical filter, so I'd not introduce any solids; clogging can happen, especially this way. Meyer Jordan advocated a bog prefilter when I had clogging. Since, I've raised my pump off the bottom and ditched the prefilter, but when I was doing such, I did catch a lot of crud I thought could indeed clog.

Could you expand on that? Not introducing solids? Is duck sh*t considered a "solid"?

You have since changed from having a prefilter, so you no longer have a prefilter? Is a solids filter a "prefilter"
Sorry about all the questions, but the vernacular is a bit confusing at times.
If you could start over, what would you go with as far as filters, and pump location?

 

[nimrod]

Considering how ducks , you may want to be flexible on your plumbing plans. Start with what you want, but plan for setting up a solids filter, just in case. Also, pick bog plants with the ducks in mind. You’ll want some that they won’t stomp flat, or eat up. Expect ducks to enjoy the bog half too.

This whole build is inspired by the damn ducks, so I'll have them in mind every step of the way! I'm hoping the ducks will help thin the bog when it starts expanding rapidly. I think I'll fence it off until the plants get established, then let the ducks in after I know they won't destroy everything.

 

[nimrod]

I built mine with the bog separate from the pond, all one liner. Built a landscape timber wall between the two, covered the wall with the liner. We have a 3 foot or so opening for the water fall back into the pond over a flat rock. Over time the bog water weeps over the entire wall into the pond. I have had no issues except excess plant growth that can redirect water flow.

I really like the idea of digging just one hole, and separating the bog with a constructed wall. Is there risk of the landscape timbers rotting and collapsing?

Do you have an additional rock wall stacked on top of the timber wall (on top the liner)? I'd like to cover the wall with something so you don't just see liner. My plan is to use flagstone to do the trimming on the whole pond, so I was hoping I could put a row of flagstone across the top of the wall.

 

[addy1]

Is there risk of the landscape timbers rotting and collapsing?

They are still solid 10 years later.

Do you have an additional rock wall stacked on top of the timber wall (on top the liner)?

yes but right now the deer have knocked most of it into the pond on the bog shelf wall. Once warmer I will stick my arms in and pull it out.

 

[brokensword]

Could you expand on that? Not introducing solids? Is duck sh*t considered a "solid"?

You have since changed from having a prefilter, so you no longer have a prefilter? Is a solids filter a "prefilter"
Sorry about all the questions, but the vernacular is a bit confusing at times.
If you could start over, what would you go with as far as filters, and pump location?

Water has impurities, some of which you can see, some you can't. The ones you can are the solids. The bog WILL break down the solids as well as the ones-you-can't but it takes more time and these solids can constrict the flow up from the bottom of the bog. This is called clogging. When this happens, the water finds other ways to rise and thus avoids a lot of the bacteria-colonized gravel in your bog, thus circumventing the purpose of a bog. The plants you put in your bog only take up the last of the 3 main organics involved; the nitrates. Nitrattes are not nearly as deadly to your fish as the first two, ammonia and nitrite. Different bacteria breaks down each.

So the idea is a bog is not designed to filter out those organics you can see. It CAN but it's not designed to do so without a cost. So, by lifting your pump up off the bottom, most of the solids remain there and do not get pumped to your bog. You're using a bog as a place to clean your water by removing much of the 3 elements above. With ducks, you're going to have to monitor and probably do some manual cleaning/vacuuming of the bottom or hope they don't pollute faster than the system can break it down.

With a lot of organics in your water, you'll battle with free-floating algae unless you provide a lot of shade. Floating plants help to do this as well as help take out what the bog misses/doesn't get.

My prefilter was just that; a filter to keep solids from getting into my bog and creating a clogged situatioin, which I had mainly because bog v1 was too small for the amount of fish I eventually had and I had my pump on the pond bottom. When I expanded, I continued the prefilter but noticed my bog plants weren't as robust as they should be and cut that filter out. Since I'm pumping 12" off the bottom, I don't get much solids going to the bog, at least nothing that can't decay and decompose so the bog plants will eventually take out. My prefilter was based on the aqurium 'filter sock' but enlarged tremendously to accomodate 4K gallons going through it an hour. I experimented with various mesh screen sizes and found 400 micron to be the limit as I'd have to rinse clean the sock almost daily with what accumulated. 200 is a good medium choice and less maintenance with 100 letting too much solid past to make much difference.

I made bog v2 much much larger. I think that's a huge key to this, in getting enough bog volume/surface area so you have more latitude re organics removal.

But in all this, I don't have ducks (the real variety as my decoys don't poop all that much) so your situation is going to have to be monitored to see how much manual cleaning needs to be done. Obviously a bog will really benefit you, though.

Hope this helps.

 

[addy1]

My prefilter is a 5 gallon bucket full of holes, cuts down the draw at any one place. It is in the 5 foot deep area about 4 feet down. Been working just fine for years now. With all the hornwort that grows there, every now and then I need to brush the hornwort back from the bucket. The other pipe is my prefilter for the clear water pump that feeds the deck ponds. It can handle the 100 plus feet of head pressure. It is a 1 inch pvc pipe cut with some tiny slits. Both pumps are external.
.

 

[nimrod]

So the idea is a bog is not designed to filter out those organics you can see. It CAN but it's not designed to do so without a cost. So, by lifting your pump up off the bottom, most of the solids remain there and do not get pumped to your bog. You're using a bog as a place to clean your water by removing much of the 3 elements above. With ducks, you're going to have to monitor and probably do some manual cleaning/vacuuming of the bottom or hope they don't pollute faster than the system can break it down.

Excellent! That is a great reply. I didn't realize that even suspended solids would be considered "solids". I was thinking solids referred to sticks/leaves that fall in and can damage a pump.

As of now, I am planning to make my bog almost 80% the size of my pond, so I am really hoping that will speed up the processing of all the duck's solids.

I am also hoping that I can make my bog deep, with a nice void under the pea-gravel to allow those solids to settle a bit. I also plan on having a large enough cleanout connected to the bog dispersion pipe, so all the muck vacuum/pumping can take place at that point. I saw something here suggesting some water jets that would help break up the solids that settle out to allow the pump to continue to move those contaminants to the bog for filtration. Not sure how that would work with having a pump in the pond, vs in a skimmer/intake bay. What are your opinions on intake bays? I am concerned a bit that the intake bay or skimmer will only let surface level water into the pump, and all the duck waste will accumulate on the pond's floor. But maybe that's not such a bad thing?

My main design principles are: simplicity, and clean aesthetics. So I am attempting to contain all my filtering/pumping/cleaning/etc within the confines of the pond itself.