Bog building, also called upflow filter, eco filter, wetland filter

[addy1]

I have one area that looks like normal ground except for always being wet. The plants have grown enough with enough root mass they have made land.

I do pull some now and then but usually leave the area alone. Lizard tail and obedient plant mainly in that area.

Other parts of the bog are under water, or above water here and there. I do yank plants about once a month to keep the path to the water fall clear.

 

[CountryEscape]

I totally agree with Poconojoe!!! Some plants like to have their crown above water, while others can be 3-5” deep. And it’s fun (before the plants grow out, to sculpt the area and make streams going through mounds of gravel. The level of the bog shouldn’t change with water evaporation as long as there is an overflow that isn’t clogged. And because of this, you always have that reason to check for encroaching plants in or next to the overflow, to make sure the water level remains the same.

 

[Kirino]

There is so much interesting information here. Not sure if it has been posted yet: is there a way to calculate the flowrate you'll end up with after the water goes through a bog? I'm building an upflow and I really need to know how big the overflow needs to be from the bog back into the main pond

 

[addy1]

Some here have put up info on that.

Me I did not worry about it. I have a 6800 gph pump, a huge bog 27x4x2.5 feet, and it works just fine. It filters 5 ponds continuously, 5 others on a timer.

 

[combatwombat]

@Kirino: whatever flow rate you put into the bog is the flow rate you’ll get out as long as you’re not choking it down with your distribution piping.

 

[Kirino]

@combatwombat well since it is entering the bog from below I was thinking of perforated piping in an area with boxes, on top of that some type of substrate (not sure yet which). I'd reckon that would slow it all down, no? With all the gravel on top.

 

[combatwombat]

I'd reckon that would slow it all down, no?

No. What goes in comes out. What will change is the velocity of the water as it travels through the substrate. But velocity in the bog does not matter when planning width of spillway. Base that on whatever the flow rate you have going into the bog.

Edit to add: You should be planning your bog flow rate by figuring out your total dynamic head which includes:

1. The elevation gain from pond water level to bog spillway.
2. Length of pipe.
3. Diameter of pipe.

Once you know all that, you can decide what flow rate you want coming out of the spillway and purchase your pump based on that.

 

[poconojoe]

If you feel you have too much going through your bog, you can add a wye after your pump. Install a ball valve on each of the two outlets of the wye. Have one go to the bog and the other return to the pond at another location. You can then fine tune how much water goes where by adjusting the ball valves.

The water flowing through my bog seems perfect.
To give you some idea of my parameters, here is a brief description of what I have:

My bog is 14 feet x 5 feet and the gravel is 12 inches deep. Mine is the basic bog, manifold covered directly with gravel. No chambers, Aqua Blox, milk crates, snorkel or centipede.

My pump is 3600 gph and has an 1-1/2" outlet.
I have 1-1/2" flex PVC from the pump directly to the bog (no wye or valves). I change over to 2" PVC from there.
My bog manifold is two 10 foot long 2" PVC pipes with slits cut in them. The slits are spaced at every 1-1/2". I faced the slits up.

Again, the flow through my bog seems perfect. Maybe I just got lucky with the size pump I already had. (3600 gph)

Hope this helps.

 

[addy1]

My bog is 14 feet x 5 feet and the gravel is 12 inches deep. Mine is the basic bog, manifold covered directly with gravel. No chambers, Aqua Blox, milk crates, snorkel or centipede.

Mine is the same, basic, pvc pipes, gravel and plants. The pvc is 2in with slits cut in it 26 feet long, two running down the length of the bog. It works great
My gravel is 2.5 feet deep or so.

 

[brokensword]

I'll chime in with another bog description; mine is 20' long, 3' wide, 3' deep. I used 4" drain pipe with slits. I layered rock on top; first 12" of 6 -8" stone, then 12" of 2" cobble, and finally 12" of pea gravel. I have (2) of these drain pipe manifolds. For my 'snorkel and vault', I placed a large plastic garbage can in the deepest part, then cut some 4" holes near the bottom. If I ever need to clean the bog, all the water will enter the garbage can where I'll have another pump to pull it out. In my case, I have two 55 gal drum pre-filters to help remove the fines from getting into the bog. As such, my bog gets gravity fed from the drums, each of which has ball valves to control how much goes into the bog.

 

[Magicno1]

Hi.
My Bog filter is now progressing well and to the point where I will be laying the spill stone in the bog wall. The bog is 12 inches deep and the spill stone is about 6 to 7 inches lower than the top stones. My question is when I line the bog with a liner how do I cut around the spill stone? My main pond liner is under and up the back of the bog so any leaks will run back into the main pond but I can’t get my head around how to finish the liner in the bog! Can I tick the liner under the last course of stones and cement around the spill stone?

Regards

Chris

 

[poconojoe]

Dont cut any liner!

My biggest worry, which turned out to be no big deal, was figuring out what the spillway height should be. That height will determine the level of water of the bog.

I found out after it was all done, I could lay more flat stones in the spillway which would actually increase the volume of water in the bog. Hope that makes sense.

Form, shape and size the spillway.
Lay the liner over your spillway and over your existing pond liner, then lay your better looking stones on top of the bog liner. If you like, You can add a scrap of liner or underlayment down on the liner to protect it before you put any stones on it.
Make sure your bog liner has a good overlap on the pond liner.

I wouldn't cement or glue anything together for a few reasons.

The cement will not look natural.

The cement will eventually break loose and it will not only look ugly all broken up, but the chunks will end up in the pond.

And... I have never had a waterfall or spillway that I built once. I'm always having to adjust or change things a bit to get the perfect look or sound from the feature.
If you permanently cement it all together, you'll be stuck with it.

 

[brokensword]

like PJ said; liner inside the pond liner, OR, you can do as I did if you haven't already put the pond liner in (I didn't re-read the whole thread, so...)--I have my pond liner come up and over my bog and actually form the liner OF my bog. So, to hide this, I stacked rock in front on the face of the bog and at the top, folded a portion and laid rock on top. So the water enters the bog from the bottom, rises, flows over the pea gravel and because of this folded lip, spills down the front face of stacked rock.

Hope this helps.

 

[Magicno1]

Thank you!
Makes sense a little more now!
I’ll form the spill then run the liner over that then put the spill stone onto that.
Thank you

 

[Bluefox]

I was asked to start a thread on how to build a bog.

This is my rendition on bog building 101.............

Building a bog:

Before you decide to build a bog, you need to know what you want its primary purpose to be.
Total pond filtration
bog filtration combined with another filter.

If you want total pond filtration using a bog;
By volume, 5-15% the size of the water volume of the pond.
By surface area, 10-30% of the pond surface area.

If you are having a large fish load or koi you would want to have the larger bog size.

My bog is 27% compared to the surface area of my pond. (I love plants and they love the bog). My only filtration is my bog.My bog is deep, most bogs are no more than 12 inches in depth.You want your water level in the bog to be lower than the pea gravel, this will make the water work to get back into the pond, through the plant roots.

If you just have a bog for some filtration (have another filter also) it can be whatever size you would like it to be.Do not pre-filter the water before it enters the bog, this will starve the bog of needed nutrients.

There are multiple ways to build a bog, I have used three different ways in my ponds.

All bog drawings show an submersible pump, I use an external, it was just easier to draw with a submersible. So you can use either a submersible or a external. Have a leaf basket in line with your pump to collect any large debris before it enters the bog.


My current bog is a raised bog.We built a wall between the pond and bog, left one area that is low for a water fall back into the pond.One piece of liner was used for the pond and bog.

This bog has a solid separation between the pond and bog

View attachment 35716


The following three bogs all have blocks, rocks stacked so water will flow through them, porous retaining wall, rock, whatever will keep the pea gravel behind the wall and out of the pond.The water will be pumped into the bog and work out back into the pond through the wall.

A partition bog can be built.Build your pond to the size and shape you want, have the bog in the pond separated by a partition.


View attachment 35717


Or

A border bog can be built.(I have used border bogs, looks really nice.)Dig a border for your pond, 12 inches deep as wide as you want.Porous stones will be placed between the bog and the pond.

View attachment 35718



Or

A island bog. An island of pea gravel, separated from the pond by a porous wall.


View attachment 35719



Once you decide what bog you want the fun begins.

You need to lay out the pvc piping. I use 2 inch below my pea gravel.You can use 1.5 inch pvc if you wish, do not go smaller.This size is to keep the piping from clogging up.

Once you know the lengths you need, the distribution pipe needs to be perforated.We cut ours approximately every 6 inches, due to the size of our bog, we wanted to make sure the water made it to the end of the pipe.

Cut about every 1 to 1.5 inches apart the length of the pipe. If you have a long pipe run make the cuts further apart.Use a circular saw to cut 1/4 to 1/3 of the way through the pipe perpendicular to the water flow.If your bog is only 3 feet in width you can get away with just one distribution pipe, wider you should use two.

Lay your pipe in the bog.I laid mine slits down, so whenever I turned the pump off pea gravel would not be able settle in the piping.But I did lay extra liner under the pvc the length of the pipes to protect the liner from the continuous water flow. You could also lay the pvc with the cuts up.

At the end of your pipe run, put in a clean out pipe. I did not put a clean out pipe in this build, it has not been missed.

View attachment 35720



Paint the cap sticking above pea gravel brown to make it less noticeable.


Shovel 3/8 inch pea gravel into the bog.Wash the best you can, but even with washing there will be silt from the gravel; the bog will clean it out.

When building your bog walls, make the walls around 6 inches over the pea gravel level. As the plants grow, the roots grow, the water level will raise. You need the extra wall space to handle the rise in the water level. Two years into having my bog I had to raise the walls about 4 inches.

Plant around 1 plant per square foot.If your pond and bog are new, leave the dirt on the plants roots.There is not enough nutrition for the plants with a new bog.
Be careful what you plant in your bog, some plants are aggressive growers.
Do not leave the plants in their pots, take them out.

plant list:

I plant hardies:

This is what I have currently:

Obediant plant
black gamecock iris
dwarf golden sweetflag
dwarf cattails
varigated snow flake-lily like plant needs to be planted about 14" under water surface.
Water Willow
green creeping Jenny
Marsh betony

4 leaf water clover
fuzzy 4 leaf water clover
mini spearwort
white star grass
penny wort
water mint
blue water forget me not
water iris soft pinkkirk strawn
4 left water clover variegated

Excellent Plants for the Bog may includefrom the net)

Arrowhead Sagitaria (zone 4-6) Summer Bloomer. Bulbing root system stores(nitrogen, potassium & phosphorous)

Canna (zone 8-10) Summer Bloomer. A bog’s best friend. This plant is a biomass factory and has amazing beauty and structure. A heavy feeder on (nitrogen, potassium & phosphorous) from April through September.

Cattails (zone 3-5) Summer Bloomer. are vigorous growers and have deep roots.

Creeping Jenny (zone 5) Spring Bloomer.

Daylily - Spring through Summer Bloomer. Surprisingly, water is the best fertilizer for daylilies. They are an excellent nutrient feeder and grow well in the shallow areas of a bog garden. Daylily come in a variety of colors and blooming times for a long lasting color in your garden.

Eyed Grass (Yellow & Blue) (zones 5-7) Spring Bloomer.

Iris - (zones 4-6) Summer Bloomers.
Common water iris. (Louisiana Iris) Great variety in colors and styles. Plant habit is spreading and untidy appearance.
Japanese variegated water iris is a strong grower late spring through fall. Iris are good at removing both nitrogen and phosphorous.
Siberian Iris are preferred for their strong, clumping habit. Most growth spring and summer but use potassium and phosphorous in summer and fall for energy storage for next year’s bloom.

Kaffir Lily (zone 7) Fall Bloomer. A bulbing lily with watermelon red flowers. Grows in cooler temps of spring and fall. Small top growth controlled.

Lobelia Cardinalis (zones 5-7) Fall Bloomer. Beautiful late summer bloom. Nice color diversity. Heavy potassium user.

Marsh Marigold (zones 2-4) Spring Bloomer. A fast growing cool temperature plant. Begins growing very early in spring producing flowers by early March and continues through April, often re-blooms in the fall when weather cools. Medium root depth and actively feeds when most plants are dormant.

Pickerel Rush (zone 3-6) Summer Bloomer. Strong summer growth and bloom. A spreading habit with a shallow root system. A strong feeder on the total nutrient system. Blue Pickerel Rush is very hardy in our area, with a long bloom season.

Rain Lily (zone 6) Fall Bloomer. Late summer and fall grower. This bulb plant has a small controlled top growth but a dense vigorous root system with storage bulbs. Strong user of phosphorous and potassium.

Rush - Variegated Striped Rush (zone 5-6) Summer Bloomer. Evergreen and continues to grow almost year-round strongest growth in summer. Roots are shallow and need oxygen. Open habit allows for under story growth.but has a large vigorous root system feeding its bulbs. Very

Slough Sedge (zone 4) Very prolific, yet clumping. Grows to 5’ high in bogs. Deep rooting habit. Bio-mass. Strong user of potassium, sulfur, calcium and sodium. Somewhat salt resistant.

Society Garlic (zone 7) Summer Bloomer. Strong summer growth. Love phosphorous.

Star Grass (zone 7) Summer Bloomer. Very controlled, medium root depth, summer fall growth. Grasses are strong feeders of potassium and sulfur.

Thalia (zone 6) Summer Bloomer. Very deep rooted. Open stem structure allows for very diverse under story growth. Summer blooming. Large storage roots.

Water Forget-Me-Not (zone 3) Spring Bloomer. Vigorous low grower. Shallow rooted. Easily pruned. Blooms from March through October.

Yellow Monkey Flower (zone 6) Spring Bloomer. Early spring growth and bloom. Deep root system.

Bog Plants:
Arrowhead
Assorted Taros
Bog Lily
Cannas
Chinese Water Chestnut
Creeping Jenny
Dwarf Horsetail
Dwarf Papyrus
Dwarf Variegated Sweetflag Giant Melon Sword
Japanese Iris
Lizard's Tail
Lousiana Iris
Pickerel Rush
Red Stemmed Sagittaria
Ribbon Grass
Ruby Creeper
Ruby Eye Arrowhead Sensitive Plant
Siberian Iris
Spider Lily
Spike Rush
Star Grass
Thalia
Variegated Spider Lily
White Bull Rush
Zebra Rush
Plants that are invasive in the Bog (Think Twice Before Planting)
Horsetail
Aquatic Mint
Chameleon Plant
Parrot's Feather
Red Stemmed Thalia
Cattails
Umbrella Palm
Yellow Iris


ok brain and fingers are tired, if there are any glaring goofs will fix .....................

WOW. A lot of info to digest. I will have to read that a few times to get my head round it all. Thanks very much for that.