Designing Wetland / Bog Filter Size and Materials

[HayFam2022]

Hi everyone!

I am excited about this giant filter, as I keep reading how integral it is to creating an ‘ecosystem’ with clear water. However, working this filter into my final vision for the pond is a challenge.

In the end, I’m planning to have the corner of the pond—nearest the road—built up with large boulders to be the highest point. With plenty of large plants and vegetation behind it, I’m hoping to create the effect that the water is flowing down into our pond from a water source back in the wooded area.

Currently:

Although this area is currently wide open, we already have this deep forest effect naturally elsewhere in our yard. Here’s an example during our Florida winter not far from the pond:

Hopefully this is making sense so far. I’d sketch it out if I was capable, but that’d just be more confusing. In short, everything in Florida is very flat, so it’s an attempt to make the pond look natural.

*Actually, I tried to draw it on my phone. I’ll include it for a good laugh

With that goal in mind, my original filter layout was L shaped around this corner of the pond. The two issues I had were the amount of liner needed and how to run the diy centipede and snorkel. So after continuing to reduce one arm of the L while expanding the other several times, I’ve now decided to keep it simple and use a simple rectangle design. Here is another sketch showing the design:

I plan to start the filter at ground level and give it a height of 2 feet.

Then I can build up the missing part of my L-shape with dirt and then place my rocks from there.

For the centipede, I plan to use 8” drain with perforations throughout and for the snorkel an 18” drain pipe set vertically. I’ve seen this used elsewhere, but I would appreciate any and all feedback!! I’m just starting to realize how much rock this will take and I don’t want to do this more than once if possible.

Feeding into the centipede will be the 3” pipe feeding from the external pump. It’s 12k gph. It will sit between the intake bay and bog filter. However I didn’t include the pump in this doodle:

I plan to fill with 4” rock, then 1.5”, and finally pea gravel at the top.

Sizing:
My pond’s surface area is 600sqft at 15x40. After adding rocks it will be more like 481sqft at 13x37.

The filter will be 14x12= 168sqft

If I’m understanding the 30% rule correctly it would be:
481 x .3 = 144.3 sqft


So that is the basic design, I’d love some feedback. Some concerns I have:

• Is filter deep enough
• Will this DIY centipede/snorkel work for this size filter
• My bog filter size vs pond size

That’s all I can think of at the moment. I’m writing from my phone and need to rest my thumb lol

 

[GBBUDD]

look at this video as a guide but you'd obviously be smaller

Some very impressive pond builds

https://whttps://www.youtube.com/watch?v=1TOMbsvXjX8 ww.youtube.com/watch?v=Hc36HtktJD0

www.gardenpondforum.com

 

[GBBUDD]

https://www.gardenpondforum.com/threads/some-very-impressive-pond-builds.26353/ take a look at the video with the dr poe

 

[HayFam2022]

https://www.gardenpondforum.com/threads/some-very-impressive-pond-builds.26353/ take a look at the video with the dr poe

Thank you for referencing these videos. After watching the Dr Poe video my filter is too close to my pond and likely too low at 2’ below my pond (for the particular look I’m going for)

I’ll have to keep watching videos and revisit my plan.

Thank you!

 

[combatwombat]

Generally good plan, yes.

Is filter deep enough

If 2' is referencing the depth of gravel in the filter, then yes, I'd say that's deep enough. I have a little more than 2' of gravel, but my filter is 5' deep if you measure from the top edge of the liner to the very bottom of the snorkel. Agree w/ your realization that 2' between bog and pond (we're talking horizontal distance not elevation, right?) is not enough. It can be done (mine is about 2' as well), but if you want multiple falls and a stream using large boulders... you can't get there in 2'.

Will this DIY centipede/snorkel work for this size filter

Sure. A bigger centipede would be better. Especially if you're not doing any matrix blocks over it. I would just buy a full stick of the 18" and use it for the centipede and the snorkel. Size of snorkel only matters to the extent that you can comfortably fit a cleanout pump in it.

My bog filter size vs pond size

30% is pretty good. If the pond will be in full sun with lots of koi and 3 kids swimming in it daily, then you could make the argument to go bigger, but lots of folks have bogs at 10-15% surface area and do just fine.

One other thought that comes to mind: With how the water will circulate from your bog to your intake, you're probably going to want to run some jets along the far side as you'll have dead areas over there.

 

[GBBUDD]

Having a stream in my opinion is priceless but in a flat area like florida it creates other issues like how do you build up the bog say 24 inches have the falls visible and then have a 1 foot waterfall into the pond or do you have a splitter in the piping and some of the water goes tot he bog and then a split in the pipe sends other gph to a waterfall and yet some other to return jets for circulation . a stream is not a must but they are nice to have

 

[addy1]

Like your drawing, nice hole!

My bog was built before snorkels centipede aqua blocks, etc. Just pea gravel and pvc pipes it works great.
2.5 feet deep.

 

[GBBUDD]

I'm not a biologist or a environmentalist but i have spent WAYYYYYYYYYYYYYY too much time with them on the job. Looked at more mud puddles and stagnant water puddles. That led me to the bogs whether to invest in the matrix bog or just the pea stone bog. as you have seen i lost that battle and built one of each to see for myself.

While the matrix bog is hardly cheap and is way over priced for what it does compared to the pea stone bog. I still feel it is worth the money . It gives the water an area where the heavy particles in the water have a place to settle and drop out of the water column. And any plant matter or left over food can settle in the what i refer to as a cave where the buffet table is set and the bacteria microbes and insects can devour the smorgasbord. it is broken down further to where the plants and gravel then take over . i have seen more bizzare creatures in the centipede and have even found koi fry swimming around

The snorkel also gives you the option to clean the finer sediment . as does the pea stone with cleanouts but you'll only get so much out of a 2 inch pipe over a 12''