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

[Jhn]

We mostly use the gas powered cut off/demo saws for cutting steel, when we need to do maintenance work on barges or making an oddball something needed for work. Occasionally use it to cut asphalt when we need to dig behind walls to keep from tearing up more parking lot or roadway than necessary. Definitely don’t see many homeowners with these.

 

[addy1]

We have a brand new electric demo saw, even though we do a lot of demo, hubby has never used it. One of these days will pass it on to somebody that will use it. His fav tool is the saw jaw, saw all, reciprocating saw......................grabs it for everything. It does prune trees nicely.

 

[GBBUDD]

It is what the hubby calls this , so for me it was what I typed without thinking about it!
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There's no right or wrong answer addy But i did just start a job recently where one crew labeled there storage area M. T
. I had not a clue what they were posting and when i asked they lol and said well what did you say reading it. These guys or at least some of them did not know how to spell or read what empty was . That problem was rectified....

 

[addy1]

lmao! that is a good one! M.T. shorthand words...........

 

[GBBUDD]

As anyone here has seen typing is certainly not my strong point. i Have little care for punctuation caps etc yeah i know it helps to tell the story but it's not my cup of tea i'd rather build a pond over type about it here . But helping out those trying there own hand at it here if it means they are successful and the fish don't suffer im all for a helping hand. So long as they are willing to help them selves.

 

[Brian Montague]

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

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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.


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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.

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Or

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


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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.

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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.

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 .....................

Dear addy 1, Many thanks for detailed info re bog and particular thanks for the comprehensive list of all year round plants. It is very much appreciated. All the best, Brian M

 

[addy1]

You are welcome. I write that long time ago.

 

[nomadh]

Love the thread and some killer ideas. That ring bog blew my mind but the one part I disagree with is the gravel. I know, it was cheap and and easy and seems obvious and natural but after having to clean them a few times I really grew to hate it. That and lava rock (because it so much lighter, ughh). I found that any submerged media unless churned or regularly churned to bleak it up will start to clog and then channel. It takes almost no difference in least resistance to rather quickly clog the slower pathways as the water then blows out the wider channels until most of the rock is like concrete with just 1 or 2 big water pathways. Sometimes within in a month or 2. It's similar to my spray bar on my trickle tower biofilter. In a year I need to u plug 2/3ds of the holes. The plus there is I unhook it from the top and scrub with a brush for 1 min. I could see a very big well built gravel filter working for even a few years but it seems it will eventually cement itself. I've talked to 10 people in the koi club that go back 40 or 50 years and all of them now curse their old gravel or lava system. I could see this work as a fluidized bed (being constantly churned) but with plants the roots will stop that. So how does this system work over years and when you do clean it what type of chore is it?

 

[nomadh]

less typing than this! Reciprocating Saw

Sawzall for us. I think that's also a name brand like skil

 

[brokensword]

Love the thread and some killer ideas. That ring bog blew my mind but the one part I disagree with is the gravel. I know, it was cheap and and easy and seems obvious and natural but after having to clean them a few times I really grew to hate it. That and lava rock (because it so much lighter, ughh). I found that any submerged media unless churned or regularly churned to bleak it up will start to clog and then channel. It takes almost no difference in least resistance to rather quickly clog the slower pathways as the water then blows out the wider channels until most of the rock is like concrete with just 1 or 2 big water pathways. Sometimes within in a month or 2. It's similar to my spray bar on my trickle tower biofilter. In a year I need to u plug 2/3ds of the holes. The plus there is I unhook it from the top and scrub with a brush for 1 min. I could see a very big well built gravel filter working for even a few years but it seems it will eventually cement itself. I've talked to 10 people in the koi club that go back 40 or 50 years and all of them now curse their old gravel or lava system. I could see this work as a fluidized bed (being constantly churned) but with plants the roots will stop that. So how does this system work over years and when you do clean it what type of chore is it?

you'll find her answer is; over 10 years and never cleaned it. This will be a mantra for most well built upflow wetland filters (bog-type filter). The maintenance needed is thinning the plants as they thrive and do their job. The more aggressive the root system, the more filtering power. That and addy's bog is very large, which is another benefit toward successful filtering. Mine is similar in size and depth. The idea is not to throw water into the bog so fast and in large volume, but rather, less and slower so any accumulate can break down and NOT channel. We use gravel as it provides a lot of surface for the denitrifying bacteria AND a substrate for plant roots.

 

[nomadh]

I won't speak for @addy1 , but I can say that our bog does not filter fines. We've considered getting a fines filter from time to time, or just DIYing a quilt batting set up for a few days, but ultimately decide that we just really aren't all that bothered by it.

I find the gravel wont filter fines too well either but I think the plant roots would. My hyacynth work like magic. And they can so starve the pond of fertilizer all the plants start to yellow even with a full fish load.

 

[Mmathis]

@nomadh Look at the mechanics of a bog. Most of us use up-flow bogs where water from the pump is pumped through a manifold (of one type or another) at the bottom of the gravel bed. Water flows upward, through the gravel and past the plant roots. Yes, there might be channeling, but if the bog is plumbed correctly, and maintained (plants cultivated), it will still be a very efficient filter. It’s been proven to work.

 

[nomadh]

you'll find her answer is; over 10 years and never cleaned it. This will be a mantra for most well built upflow wetland filters (bog-type filter). The maintenance needed is thinning the plants as they thrive and do their job. The more aggressive the root system, the more filtering power. That and addy's bog is very large, which is another benefit toward successful filtering. Mine is similar in size and depth. The idea is not to throw water into the bog so fast and in large volume, but rather, less and slower so any accumulate can break down and NOT channel. We use gravel as it provides a lot of surface for the denitrifying bacteria AND a substrate for plant roots.

I think at the time I didnt have room for a huge bog so my problems added up real fast but even that small one I had to thin the plants and unbind the roots from all the gravel they keep taking with them.
At a koi meeting we had a filter expert from marineland he designed and maintained small and gargantuan systems. He explained that the bacteria that broke down the waste products are fully aerobic and should never be submerged. They actually drown and turn anaerobic (toxic) in a few hours if flow stops. He saw submerged biofilter where the submerged biofilt was off a day in summer and the fish were ok until turning back on and killed many of the fish. He showed how an enclosed trickle tower or any filter media kept wet but never submerged had dozens of times more bacteria per sq ft.
My mother in law has a pond and I redesigned it after aquaponics type rock design almost killed most her fish. I made it about1 ft deep and 5x6 ft. I just skipped the rock and put in taro, water hyacynch and parrots feather. It grows like crazy and looks beautiful. No substrate needed. Now 1 or 2 times a yr I just lift up the root mass and saw chunks off to give away or mulch. If too much muck I just sump pump it to garden. I don't worry about separating gravel from roots or gravel getting into compost pile. The pump creates some as it falls into the bog and then again as it waterfalls into the pond. I'd still like to add more biofilter for her but with her fish load it's worked for years.

 

[Jhn]

Had an 18” gravel manifold bog for 10 years and had no issues with it other than it being undersized for my pond and stocking level. So, I enlarged it and redesigned into a water matrix block/snorkel/centipede bog, this lets the fines settle out into the snorkel and can be pumped out as needed, so not really worried about channeling happening in it. Been keeping ponds this way a loooong time, using bogs and plants as the filter and have never had a fish die off or any issues for that matter.

 

[poconojoe]

This is not based on any science. It's just my thoughts on the subject...
I think if you have your manifold disperse the water thoroughly, you shouldn't have a problem. The more of a spread you get, the less chance of getting a buildup in one spot.
I used two ten foot pieces of 2" PVC for my manifold. I cut slits 1/3 through the 2" PVC and spaced them 1-1/2" apart. My bog is only 5 feet wide.