Bog Build

[brokensword]

A bog filter, more accurately named 'upflow wetland filter', has many advantages and is almost a miracle cure all for green water, new pond syndrome, and keeping your water healthy and clear. A bog filter is a biological filter, and though it will also mechanically filter the water, is not purposed for this. Doing so, will result in clogging and necessitate cleaning for it to function efficient'y again. Keeping the pond pump off the bottom will go a long way toward keeping solids out of the bog.

Below, a cross section and front view of one way to build a bog. There are variations with some more advantages as you go both deeper and provide more surface area for bacteria to colonize as well as more dwell time. The most basic of bog filters would see ONLY the top 12" of pea gravel with 2" pvc manifolds and no clean out. Water will be pumped to the bottom via a feed from the pump and exit via slits cut every 2 - 6", depending on length of run and size of manifold.

For cleaning purposes, risers with screw caps can be part of the manifold system and you use your pond pump to push debris out of these risers after unscrewing the cap. This will not clean the actual pea gravel, just the manifolds.

A second type of bog design allows for an open space below the stone as well as a way to back flush from the top and clean by using a stack where an auxiliary pump can be placed at the lowest point of the bog. Larger round stone or Aqua-blox type structures can create this open area where longer dwell time can occur.

In either design, anti-siphon techniques should be employed to eliminate possible draining of the bog when power is lost. This can be accomplished with either a tee and screw cap on the input feed at it's high point, or a small hole drilled in a similar place.

In the below design, twin 4" corrugated plastic drain pipe was laid in a trench lower than the bog bottom, slits cut every 6" and pointed upward, connected to a stack/clean out at the lowest point of the bog. Sides are carved in the shape of a 'V' to facilitate back flushing efficiency. 12" of 8" round stone laid over top the manifolds for the first layer. Second layer is 12" of 2" round stone followed by 12" of 3/8" pea gravel in which the plants are placed.

The sides and back of a bog should be at least 6" higher than the front to provide an outlet for the rising water (and keep the water from wicking over and out), or auxiliary outlet ports can be used (i.e. pipe or weir). The liner should also be 6" taller on the sides and back.

Low growing aggressive but shallow rooted plants take up more nutrients than taller, slower growing types. The only maintenance for a bog filter is thinning of these plants to allow the active growth to happen, and a pre-winter cut down.

bog build design cross section.jpg (86.36 KiB) Viewed 882 times

bog build design - front view.jpg (57.33 KiB) Viewed 882 times

[j.w]

Great job on explaining it all!

[brokensword]

Quick video of an example of a simple bog build;

* showing a dual leg schedule 40 pvc manifold. Slits are cut 1/3 the way through using a circular saw, vertical risers with screw on caps are attached at the end for cleaning manifolds if necessary. Slits can be anywhere between 2 and 6" distance between depending on length of manifolds. Shorter leg measurement, shorter distance between slits. Slits can be cut facing up or down.
* any size bog helps but the number to try for is 30% of the pond surface.
* site is prepped for digging
* front is edged (in this case, with concrete stone but ground contact treated wood or even soil can also be used), which should be 6" min higher than pond level and 6" lower than the bog sides and back
* outside edges, sides and back, are lifted higher than grade/pond water height; liner should go over final height then finished with deco rock over top. Again, the bog can be build using anything that can contain the pea gravel and is higher than the final pond water level.
* dig down or build up to desired final height; 12" minimum for pea gravel layer where the plants will be placed upon completion.
* liner is placed;
* pvc manifold is placed
* hose is attached (though not shown, a tee and screw cap is placed inline at the high point where the hose lifts over the bog edge and should have a 1/4" hole to release the vacuum; placing the hose over the front edge and thus over the liner will guarantee any leakage remains in the pond system). At the bog, a ball valve should be used to control how much water enters.
*pea gravel is placed on the manifold and over the liner. The final pea gravel level should be 6" lower than the back and sides of the bog and even with the front bog edge facing the pond. The hose enters over the front bog wall and is covered by the pea gravel. Water will rise, then pour over the front to help oxygenate as well as provide another water fall/overflow. By placing rocks on top at the front edge, water can be directed in such a way that there are streams instead of a wall/sheet of water going over. There are more than a few options.
*place plants that are shallow rooted and aggressive growers will do the most re nutrient uptake.

siphon release.jpg (23.67 KiB) Viewed 872 times

[rubyduby]

This is a terrific explanation for those thinking of incorporating a bog into their system...it is the way to go, that's for sure...but since I could not have one I will remain envious!

[brokensword]

This is a terrific explanation for those thinking of incorporating a bog into their system...it is the way to go, that's for sure...but since I could not have one I will remain envious!

you and @j.w ; I'm gonna wear both of you down until you beg to have a bog! heh heh, just watch!


You know, you can always have planter style 'bogs' and can turn that area above your waterfall (if I remember it correctly) into some sort of biofilter-boglike beastie, ya know! It may take a couple pond seasons, but that ol' LPS thing will kick in, you'll scrutinize your yard, figure; hmm, don't REALLY need THAT tree...can expand THAT way...squeeze in a perfect lil bog filter THERE and voila! got brokensword off my back!


yeah, that's the way I see it going...! :mrgreen:

[j.w]

This is a terrific explanation for those thinking of incorporating a bog into their system...it is the way to go, that's for sure...but since I could not have one I will remain envious!

you and @j.w ; I'm gonna wear both of you down until you beg to have a bog! heh heh, just watch!


You know, you can always have planter style 'bogs' and can turn that area above your waterfall (if I remember it correctly) into some sort of biofilter-boglike beastie, ya know! It may take a couple pond seasons, but that ol' LPS thing will kick in, you'll scrutinize your yard, figure; hmm, don't REALLY need THAT tree...can expand THAT way...squeeze in a perfect lil bog filter THERE and voila! got brokensword off my back!


yeah, that's the way I see it going...! :mrgreen:

I really doubt you can change my mind but nice try. I am all for less no more projects for the pond deals. Getting more aged to perfection each year but my lazy bones are coming out also :arrow:

[brokensword]

I really doubt you can change my mind but nice try. I am all for less no more projects for the pond deals. Getting more aged to perfection each year but my lazy bones are coming out also :arrow:

external-content.duckduckgo.gif (76.02 KiB) Viewed 857 times

[j.w]

I really doubt you can change my mind but nice try. I am all for less no more projects for the pond deals. Getting more aged to perfection each year but my lazy bones are coming out also :arrow:

external-content.duckduckgo.gif

Yep and that's one thing that won't be gettin tossed to the curb! If I can walk, I shall do it till death do I part

[brokensword]

Yep and that's one thing that won't be gettin tossed to the curb! If I can walk, I shall do it till death do I part

oh, did I mistakenly NOT include a shovel in that walking bones hands? You know, digging a hole for a bog? I shall endeavor to rectify that situation, m'am!! :idea:

[darkmuse]

A bog filter, more accurately named 'upflow wetland filter', has many advantages and is almost a miracle cure all for green water, new pond syndrome, and keeping your water healthy and clear. A bog filter is a biological filter, and though it will also mechanically filter the water, is not purposed for this. Doing so, will result in clogging and necessitate cleaning for it to function efficient'y again. Keeping the pond pump off the bottom will go a long way toward keeping solids out of the bog.

Below, a cross section and front view of one way to build a bog. There are variations with some more advantages as you go both deeper and provide more surface area for bacteria to colonize as well as more dwell time. The most basic of bog filters would see ONLY the top 12" of pea gravel with 2" pvc manifolds and no clean out. Water will be pumped to the bottom via a feed from the pump and exit via slits cut every 2 - 6", depending on length of run and size of manifold.

For cleaning purposes, risers with screw caps can be part of the manifold system and you use your pond pump to push debris out of these risers after unscrewing the cap. This will not clean the actual pea gravel, just the manifolds.

A second type of bog design allows for an open space below the stone as well as a way to back flush from the top and clean by using a stack where an auxiliary pump can be placed at the lowest point of the bog. Larger round stone or Aqua-blox type structures can create this open area where longer dwell time can occur.

In either design, anti-siphon techniques should be employed to eliminate possible draining of the bog when power is lost. This can be accomplished with either a tee and screw cap on the input feed at it's high point, or a small hole drilled in a similar place.

In the below design, twin 4" corrugated plastic drain pipe was laid in a trench lower than the bog bottom, slits cut every 6" and pointed upward, connected to a stack/clean out at the lowest point of the bog. Sides are carved in the shape of a 'V' to facilitate back flushing efficiency. 12" of 8" round stone laid over top the manifolds for the first layer. Second layer is 12" of 2" round stone followed by 12" of 3/8" pea gravel in which the plants are placed.

The sides and back of a bog should be at least 6" higher than the front to provide an outlet for the rising water (and keep the water from wicking over and out), or auxiliary outlet ports can be used (i.e. pipe or weir). The liner should also be 6" taller on the sides and back.

Low growing aggressive but shallow rooted plants take up more nutrients than taller, slower growing types. The only maintenance for a bog filter is thinning of these plants to allow the active growth to happen, and a pre-winter cut down.

bog build design cross section.jpg

bog build design - front view.jpg

I've heard of using Aquablox and centipedes, what do you think of that system? I like the layers of stone. Do the ducks eat your plants? Had a mallard couple do that once to mine. Good thing I let the dog out a lot!

[brokensword]

I've heard of using Aquablox and centipedes, what do you think of that system? I like the layers of stone. Do the ducks eat your plants? Had a mallard couple do that once to mine. Good thing I let the dog out a lot!

I think Aquablox as a concept is brilliant, but the cost? Not so much. I did similarly with the large round stones at the first layer of my bog. Not as much dwelling space/time, but enough. And the centipede to snorkel portion I DIY'd, so in essence, that's what I'm doing. A bog along with lots of plants is the key to balancing and not doing much to keep it that way!

[rubyduby]

This is a terrific explanation for those thinking of incorporating a bog into their system...it is the way to go, that's for sure...but since I could not have one I will remain envious!

you and @j.w ; I'm gonna wear both of you down until you beg to have a bog! heh heh, just watch!


You know, you can always have planter style 'bogs' and can turn that area above your waterfall (if I remember it correctly) into some sort of biofilter-boglike beastie, ya know! It may take a couple pond seasons, but that ol' LPS thing will kick in, you'll scrutinize your yard, figure; hmm, don't REALLY need THAT tree...can expand THAT way...squeeze in a perfect lil bog filter THERE and voila! got brokensword off my back!


yeah, that's the way I see it going...! :mrgreen:

Bog, bog, bog, blah, blah, blah....