Redesign of bog/wetland filter

[Jhn]

So broke down and decided to redo my bog. Mostly because I am tinkerer by nature and can’t leave well enough alone. Anyhow, I am changing my upflow 6’x8’x 18” deep bog to a roughly 12’x12’x 3’ deep bog, with aqua blocks centipede and snorkel. It is above ground, so I framed it out with 6x6’s, pinning them together with rebar and 100d nails. It is fed by 3000gph aquascape pump in a skimmer, then will dump back into the main pond, which is 35 or 40 feet long by 16’ wide.

Even attached pics of the beginning of construction for those that don’t want to waste time reading my nonsense. The old bog can still be seen sitting in the middle of the new one. One species of purple iris will not be going back in the bog in 2 years since I added it, it has grown massive roots down to the bottom of the old bog.

 

[poconojoe]

Thanks for your post and especially the pictures. Looking forward to more pictures as you progress.

I'm planning on adding a bog filter this Spring and I have some ideas in my head and one idea is similar to what you are doing.

I'm very handy, but I'm no carpenter. I'm an electrician by trade, but have delved into the other trades over the years.

I'd like to have the bog water return to my pond via my current waterfall. My problem is building up the grade to that height. I have sort of a mound that my waterfall sits on. The ground around it slopes down. Not a terrible drop in grade, but you know how that goes...start filling it in and I'm sure it will take more fill than I'd like to deal with.

I want to make sure I have good support. I don't want the bog to collapse. I'm sure all that pea gravel will have a lot of weight to it.

I had a few thoughts. One was to build it up with soil and hold it all together with large rocks. I'm a skeptical about that idea.

The second idea was exactly as you stated. Build a wooden frame and secure it by drilling holes in it and hammering rebar into the ground. Maybe use lag bolts to connect them. Or look into your 100d nail idea. 100d...that's pretty big...right?

I'm not sure about the terminology, but I see how landscapers build retaining walls where they have wood every so often extending perpendicular inward as an anchor.

Then I'd have to fill it with enough soil to get the right height. Hopefully I can pack the soil enough to minimize future settling.

Then there's the block wall idea. Secured with rebar and concrete. I'm thinking that's a bit too permanent.

Anyway, sorry for the long post.

Looking forward to following your build. It's still a bit cold at night here, so I probably won't start for a few weeks or maybe a month.

 

[GBBUDD]

I know you'll wrap the pt before you install the rubber. but what I'm finding is insiuide the bog with one plant that I have and it's unknown how many other plants have very aggressive roots. for that reason I have thought about 1. Azek 1/2 " 4x8 sheet cut in half so the top 2 feet are protected. virtually bullet proof from roots puncturing the rubber. 2. Fiberglass doing the same thing. The Azek is recycled milk crates and infused paper bags will not rot ... The fiberglass is similar but I'm less comfortable with it as it's only 1/8 inch thick. both can be found at home depot..

 

[addy1]

12’x12’x 3’ deep bog,

Neat you will love it! Mine is around 27'x4.5'x2.5' deep it works great, just pea gravel and pvc pipes.
I had to build up my down slope side with a lot of dirt. A lot of the pond dig out dirt ended up being the dirt berm that supports the bog. I would put down the dirt and compact it with the tractor, running over it a lot, esp after rains. it has held up just fine.

 

[Jhn]

@poconojoe 100d galvanized nails are the biggest ones they have at Lowe’s and HD, either 8”,10” or 12” long. You could frame it out with wood the bury the perimeter of the bog and compact around it with the dirt you are excavating to create the bog.

@GBBUDD definitely going to use your idea of putting some type of pvc/plastic sheets (whatever my HD has) in the top 2 feet of the bog to protect the rubber liner from overly aggressive roots.

 

[Jhn]

Got everything dug out now just need to get the liner and some fabric underlay. Then rock, which will come in via flatbed truck. Also, thinking about moving Some of the sand stone rocks and building a ramp up to the top of the bog, so the turtles have access to it.

 

[poconojoe]

100d nails...more like spikes! I'll have to look for them when I go to Lowe's.

 

[GBBUDD]

The mistake I made with my bog was not making the sides high enough for root growth / Plants and the water rising.

 

[addy1]

Same here I had 4 inches over the gravel, over time I have had to add about two more inches.

 

[poconojoe]

Same here I had 4 inches over the gravel, over time I have had to add about two more inches.

So, what's the exact cause of this? Root growth? Really? Do I need to build my sides higher than I actually need? Or just don't completely fill it with pea gravel until things settle? Most agree that the bog should be 12"-14" deep. What depth should I aim for? Should I go for 18"? I guess deeper can't hurt.

 

[Alice_Bee]

mine is half inch plywood with 2x 4's and the entire structure wrapped with pipe strap, then rock on the outside. Measures 4 ft x 8ft x 2 ft deep. Needs trex mounted to exposed liner on the interior walls. Maybe while I am off this year.
No gravel, one big aquablock, I grow lilies in it. still keeps pond clear, water enters at the top, exits 8 ft away at the top, debris drops while crossing the "bog".
this pic is inside the bog, my lilies are starting to sprout.
And the pond below is clear, there is no other filter on this pond.

.

And this is the pond below, today. (couldn't find a recent pic so I shot these)

 

[GBBUDD]

what I was saying was my error with the bog is I anticipated bogs water level and stone to be x and I only had the top of containment just 4 inches higher well by the time the roots grew plants blocked water flow the 4 inches disappeared quickly even your liner at a fold where the water is only and inch or two from the top edge can WHICK causing a leak. yes rubber in a fold two its self can act like a sponge and climb up over the top being only an inch or two I know it sounds impossible but it's not

 

[poconojoe]

Good information here.
I guess it's best to keep the gravel lower than one would think from the start. The exposed vertical liner can always be hidden by placing stones on top of the gravel along the edges.

 

[addy1]

I have liner you can see in the winter, in the bog, in the summer poof plants cover it. I don't worry about it. So have plenty of rocks I could stack on the edge, but have not.

 

[Jhn]

Had that issue with the smaller bog I am replacing. Plants growing like crazy end up forcing water up and over in spots. Will definitely be leaving plenty of excess liner to adjust the height on this new build. Am planning to leave it about 6” down from the top though to start.