Bog Build With Settling Chamber

[TurtTown]

Hi Garden Pond Forum!

This is my second thread and my first one helped me greatly as I am now well on my way to a completely DIY pond and bog. Thank you! Here, I'm sharing the early stage of my pond bog build and hoping for feedback as there is so much knowledge in the community that exceeds mine. Attached are photos of my concrete infrastructure. It's a 8' x 32" x 3' depth bog and a 4' x 2' x 2' depth settling chamber below that. The settling chamber will be isolated by 4 rebar reinforced concrete slabs that will sit on the shelves above the settling chamber. The bottom is pitched down to collect in the back of the settling chamber. The side shelves will support the concrete slabs which will support large river stones that transition to pea gravel for the upper fill. The gaps in the slabs will allow for space to pump water down into the settling chamber, have a cleanout pipe, and to allow water to go up through the supported rock. I'm hoping this complex design will achieve my goals of creating water filtration, large debris settlement, and easy cleanout. The overall pond volume is 2,100 gallons, and the 3000GPH pump will split it's flow to the bottom and top of bog. This is to keep bog flow slow enough for filtration and to provide an anti syphon effect when the pump is off. This weekend I will be installing 45mil epdm liner, the inflow pipe, and the slabs will be placed on the support shelves. Folding the liner into such a strange space is going to be a mess, full of folds, and I'm concerned about two things: 1) Maintaining a flat bottom to ensure easy backflow of materials down into the settling chamber during cleanout. 2) Keeping the liner from cracking when folds are placed under heavy force. Here's what I'm thinking:

Step 1: Put down epdm rubber squares on the bottom and on side shelves of bog as a flexible underlayment.
Step 2: Put down the main epdm liner and do my best with origami to minimize folds. The folds will not be visible but I do not want places with large force to be on top of excessive folding.
Step 3: Fill the bog with water to press the rubber into place.
Step 4: Drain water out of the bog.
Step 5: Smoother the shelves that will support the concrete slabs (separating the rock for the settlement chamber) with loctite PL roof and flashing goo.
Step 6: Smoother the sloped floor of the bog (now full of wrinkles) with loctite PL roof and flashing goo.
Step 7: Place cut pieces of epdm rubber on top of the loctite goo so as to create a flat surface and extra cushion.
Step 8: Install slabs, large river rock, medium river rock, and about 2.5' depth of pea gravel.

My hope here is that the layers of rubber/rubber/loctite PL roofing and flashing/rubber will provide a slightly flexible cushion preventing the weight of the slabs and stone on the creases from future cracks and leaks in the main rubber liner. It's complex but I'm optimistic. What do you think?

Thanks!

Andrew

 

[TurtTown]

Just after posting I had another interesting idea. What if instead of using the loctite PL roofing and flashing to fill the gaps formed by folds I instead put a layer of mortar on top? I know mortar is commonly used to secure rocks in water features on top on epdm rubber. Would there be any drawbacks here? It would fill gaps to reduce compression on the folds and also make the bottom of the bog flat so that debris would flow down during a backflush. Seems like another solution. I have also included a picture of the 4 rebar enforced slabs that will sit on the side shelves to separate the setting chamber from the rocks above.

Thanks again!

Andrew

 

[sissy]

I just did stock tank filters with lava rock in them . My dad and i built a pond on our farm and that is what he used back in 1960 and the pond is still there and the owners that bought the farm back in 1986 still use la\va rock filters my dad and I built with stock tanks . They just had to buy a new stock tank . I mean they don't last forever .

 

[TurtTown]

I just did stock tank filters with lava rock in them . My dad and i built a pond on our farm and that is what he used back in 1960 and the pond is still there and the owners that bought the farm back in 1986 still use la\va rock filters my dad and I built with stock tanks . They just had to buy a new stock tank . I mean they don't last forever .

Hi Sissy,

Thank you for sharing your experience with pond filtration. It's reassuring that so many methods are effective and can last a long time! Longevity is certainly a big goal of mine too. As mentioned above, my biggest concern is how to protect epdm folds from cracking under high pressure. I'm leaning toward a thick coat of loctite PL roof and flashing with a flat layer of epdm rubber to sandwich it in instead of using a thick layer of mortar. Maybe if the mortar crumbles with age it might be crunchy on the rubber...

Thanks!

Andrew

 

[GBBUDD]

Step 1: Put down epdm rubber squares on the bottom and on side shelves of bog as a flexible underlayment. I would make sure all concrete edges are rounded over and there are no large gaps or protruding clumps.
Step 2: Put down the main epdm liner and do my best with origami to minimize folds. The folds will not be visible but I do not want places with large force to be on top of excessive folding. Folds will most certainly be visible no way around that BUT you can have 90% of the folds face in one direction and in doing so make the folds less noticible from the main viewing area. i would also without question seam the folds or simply caulk the them to prevent debris from getting in and under the folds.
Step 3: Fill the bog with water to press the rubber into place. correct but be careful not to stretch it as it has memory and can tear over time
Step 4: Drain water out of the bog.
Step 5: Smoother the shelves that will support the concrete slabs (separating the rock for the settlement chamber) with loctite PL roof and flashing goo.
Step 6: Smoother the sloped floor of the bog (now full of wrinkles) with loctite PL roof and flashing goo.
Step 7: Place cut pieces of epdm rubber on top of the loctite goo so as to create a flat surface and extra cushion.
Step 8: Install slabs, large river rock, medium river rock, and about 2.5' depth of pea gravel.

One other option because you will have a lot of folds is to make bib liners. this is a tecnique used in making waterfalls and stream. Once you get the liner as best you can again wrinkles will be everywhere. is to cut rectangular pieces of epdm and glue them over the one side at a time with caulking hiding the folds.

As i am thinking about this i am wondering about using pvc sheets they have black pvc sheets in 3/4 , 1/2 and 1/4" 4x8 sheets but it can be extremely sharp good news it is easy to work with just like wood and a router can be used to make rounded edges caulk the edges and seams with a polyurethane caulk this should keep 99% of the waste out from getting under the pvc and you can have the pvc end at your trench. will it be easy no will it be a lot of work no . it will need to be relatively tight to the liner it can be out 3 inches or something. but it would be worth it in my eyes to do one of the two in a rectangular box raised pond.

 

[TurtTown]

One other option because you will have a lot of folds is to make bib liners. this is a tecnique used in making waterfalls and stream. Once you get the liner as best you can again wrinkles will be everywhere. is to cut rectangular pieces of epdm and glue them over the one side at a time with caulking hiding the folds.

As i am thinking about this i am wondering about using pvc sheets they have black pvc sheets in 3/4 , 1/2 and 1/4" 4x8 sheets but it can be extremely sharp good news it is easy to work with just like wood and a router can be used to make rounded edges caulk the edges and seams with a polyurethane caulk this should keep 99% of the waste out from getting under the pvc and you can have the pvc end at your trench. will it be easy no will it be a lot of work no . it will need to be relatively tight to the liner it can be out 3 inches or something. but it would be worth it in my eyes to do one of the two in a rectangular box raised pond.

Hi GBBUDD!

Thank you for the amazing reply and thinking outside the " box. " Your description of a bib sounds exactly like my current plan to place down wrinkly EPDM, cover it with a rubbery goo (I'm using loctite PL roofing and flashing) and then placing a flat patch of EPDM on top. I'm glad to hear this method is used for waterfeatures. PVC seems like a great flat option too but I'm now pretty set on the plan listed in my initial post since I have all the materials.

Thanks again!

Andrew

 

[TurtTown]

Here's a progress report: Today I cut the epdm. First I placed an epdm "underlayment." Then I put down the main liner. It was supposed to be overcast and but ended up being full sun. The heat on the black rubber made progress impossible. Here are the pics so far. The wrinkles are out of control but I'm optimistic that I can make it less chaotic on a less sunny day. Thanks again for the replies!

 

[bagsmom]

We were just talking today - reminiscing about the pond build and how once the liner and overlayment were in, I couldn't work past 10:00 AM without getting burned! You are going to love your bog filter. I made mine with a settling chamber and clean-out snorkel. The filter works so well, there is never anything to clean out! It was almost disappointing!

Here's a progress report: Today I cut the epdm. First I placed an epdm "underlayment." Then I put down the main liner. It was supposed to be overcast and but ended up being full sun. The heat on the black rubber made progress impossible. Here are the pics so far. The wrinkles are out of control but I'm optimistic that I can make it less chaotic on a less sunny day. Thanks again for the replie

 

[GBBUDD]

Thats

We were just talking today - reminiscing about the pond build and how once the liner and overlayment were in, I couldn't work past 10:00 AM without getting burned! You are going to love your bog filter. I made mine with a settling chamber and clean-out snorkel. The filter works so well, there is never anything to clean out! It was almost disappointing!

Why I added a bead filter to my setup. The bog takes nothing out we constantly add food, fish produce tons of waste. They tell us to to prefilled our bogs. That we don't want to starve the plants. I don't think in a Hobbie perspective that we can ever remove too much. Sure there is equipment out there thatcan filter out everything like rodi units. But trust me try to use that with pond water and you'll be buying new expensive cartridges daily. The brown water that I get when I back wash is only half the water my pump pulls in as the outfeed from the pump splits one 3" to the bog and one 3" to the bead. More than happy to see some waste be dumped out of the pond. And these plants dont seem to be under nurished. As its still April here in Ct.

 

[sissy]

I just saw on a pond show here where the coompany did a spray on non toxic liner for decrative side ponds on a home in Georgia . The pond show is produced by a pond building company in NC . They never said the price so guessing it was not cheap . They were rectangular ponds going up each side of the side walk . I did not here them say the size of them either . But looking at the guys standing there doing it they may have been 20 ft long by 10 feet wide It was a ultra modern house i went on their sight and could not find any more info

 

[TurtTown]

Thank you for the great replies! I feel very supportive in this pond endeavor where every pond is so unique. I considered liquid rubber for my unusually shaped bog and a spray on product sounds really interesting. I bet it's expensive too. I decided against the paint on rubber knowing that ultimately all concrete will crack and if the crack is big enough, the liquid rubber will fail too. I've had some time to work on my liner and I was shocked at how manageable the folds were. I'm no longer worried about placing large loads on wrinkles and was able to place my concrete slabs down (these separate the settling chamber from the bog rocks) without any compressed folds. I've attached a picture of my progress but there's still a lot to do. I'll keep updating my progress.

Thanks,

Andrew

 

[TurtTown]

It's been a productive few weeks and the bog is well on it's way! Next, I'll be filling it with large river stones followed by smaller river stones and lastly pea gravel and water. The photos show how most of the wrinkles were organized with folds. The excessive folds are due to the settling chamber set below the main bog. This settling chamber has 3 slabs of concrete to hold up the rocks above and isolate it. I only used one "bib" to smooth out the bottom and assist materials to flow back into the settling chamber during a cleanout. The photos also include the plumbing for pumping water under the slabs and a 2" cleanout pipe. Also, there's now a very prominent bridge across the center. This is meant strengthen the overall structure. The bog doubles as a 5' retaining wall on the edge of my future patio. With water and stone pushing at the side, I've done a lot of engineering to keep it strong and the bridge with all its rebar, straps it together. It's a shame to lose some of the bog surface area for plants but the bridge gives me a lot of piece of mind for the longevity of the project.

Thanks again for all the great feedback!

Andrew

 

[GBBUDD]

Well i have to admit it looks like you did a lot of work smoothing out the wrinkles. I would consider caulking or waterfall foaming them all. The reason I say this and it is going to the next level. Is they are pockets were sediment can get in and get trapped. Not that it's all bad but with a formal garden when the bio film starts to grow it will help hide the seams that much more. Also if you looking at any plants caulking will help to keep the roots from getting in there making it impossible to remove them.

 

[TurtTown]

Well i have to admit it looks like you did a lot of work smoothing out the wrinkles. I would consider caulking or waterfall foaming them all. The reason I say this and it is going to the next level. Is they are pockets were sediment can get in and get trapped. Not that it's all bad but with a formal garden when the bio film starts to grow it will help hide the seams that much more. Also if you looking at any plants caulking will help to keep the roots from getting in there making it impossible to remove them.

Thank you for such good advice. I was not going to seal the seams since the bog rocks would push them to the sides and conceal them from sight. I had not considered plant roots! I will now seal them before I fill it up. Thanks again!