Bog construction question

[kelpie]

thanks for that Lisak1. I've been overthinking it a bit 2" pipe and gravel seems to be the way I'm heading.. (Although I do have some 41mm pipe left over from another job.) I'll get the bog filter as large as I can in the space available.. but away from the pear tree.

Current plan is to have my TNB strainers feeding the 10,000 pump, from there via 2" pipe to the T piece and ball valves. Getting it into the bog should be easy enough, mainly by stealing the designs seen elsewhere around here ( ) Getting it out is still a question to be answered.. the output from the bog is about 3m away from the waterfall into the pond... a stream seems the obvious choice, just need to figure out the logistics of getting the bog filter water and bypass water (which will be at different pressures and velocities into the stream, from there a simple job of getting it over the waterfall... how hard can that be? LOL.. Some sort of header tank perhaps?

 

[poconojoe]

Yep, if you research it, you'll read many conflicting statements.
Some say any deeper than 12" of gravel and you'll have a problem due to lack of oxygen which will prohibit healthy beneficial bacteria from colonizing. That has been debunked by Lisa as she stated in her last post. Her bog is 4 feet deep!

I think as long as you adhere to the very basics of it, you will be fine.

I used wide sweeping elbows instead of standard short ones where I could and a wye instead of a Tee, thinking there would be less constricting flow. I really don't think that was neccessary because when I open one of my clean-out stacks, the flow is massive.

My pump is a 3600gph and I think it flows nicely. The bog works great.

 

[kelpie]

Nice one addy, lots of useful info there,

 

[poconojoe]

Depending on your climate, you may have to shut the bog off for the winter.
If you shut your bog pump off you might get a natural backflow if you don't break the suction. This will drain water out of your bog and you don't want that. Plants will dry up and die.
A union can be used at the high point of your bog feed or inlet. This way you can break the suction by opening the union. I used a Fernco rubber coupling, but I'm going to change that to a more secure PVC union.

Oh, I got away with running mine all winter with no problems. I thought the water from the bog would pour over the top of the frozen pond and escape onto the ground. That didn't happen because the flow out of the bog kept an opening in the ice. I kept my deicer nearby that area just in case, but it wasn't necessary.

 

[kelpie]

In a normal winter there are perhaps 5 days of the year where water will freeze, in a bad one maybe 15.. I'm thinking a couple of ball valves at the split between bypass and bog filter would allow the bog 'loop' to be isolated from the main flow.. have to see how it goes with that. one of the advantages of the location is that it is sheltered quite well from the north winds.

 

[kelpie]

anyone used perforated hose? the type of thing they use on land drains, or french drains as they are known over here? The flow is meant to go in the opposite direction to a bog filter, but seems it might work

 

[mrsclem]

The flexible version would be prone to being crushed and the rigid has large holes that could allow gravel to clog the pipe. I started out by drilling holes, it clogged in less than a year. Slits seem the way to go.

 

[kelpie]

probably a lot cheaper too using 40mm.

 

[Lisak1]

We freeze HARD - Chicago winters - and never turn the bog off. But ours waterfalls into the pond. A different method of construction may not lend itself to running all winter.

 

[Lisak1]

I wouldn't recommend anything that could collapse. What a nightmare that would be! We actually didn't use PVC piping - we used one of these:

This is called a centipede and snorkel. The centipede is the manifold, the snorkel allows access to the bottom of the bog, if we were ever to need a clean out. I dropped a pump down there a few springs ago - nothing but clear water.

Now you know why my bog is four feet deep!

 

[kelpie]

just had a google of centipede and snorkel... appears to be at least one seller in the uk. but at £500. hmm, bit too rich for me.

the pipe I alluded to, designed to drain wet ground, and usually covered in 12" of gravel is this; comes in 60mm, 80mm and 100mm sizes.

 

[Lisak1]

Yeah... the pre-built components aren't cheap. But like I said, when we were building there wasn't a whole lot of information out there. We went with what we were told would work. Would I do it differently today? Maybe. But it works great, so in my mind it was money well spent.

 

[mrsclem]

just had a google of centipede and snorkel... appears to be at least one seller in the uk. but at £500. hmm, bit too rich for me.

the pipe I alluded to, designed to drain wet ground, and usually covered in 12" of gravel is this; comes in 60mm, 80mm and 100mm sizes.
View attachment 137831

We have used both the 3&4" of that pipe in our yard. If you step on it, it crushes.

 

[GBBUDD]

Best way is to design so the bog does not back drain to the pond by the pipes. If you pond can handle that amount of water your golden. A back check valve / is similar to a check valve but when the power goes out the check opens instead of closes and let's air in breaking the siphon. Or a small hole in tge pipe in the waterfall area that yes will spit water when pump in running but will also break tge siphon.

 

[brokensword]

just had a google of centipede and snorkel... appears to be at least one seller in the uk. but at £500. hmm, bit too rich for me.

the pipe I alluded to, designed to drain wet ground, and usually covered in 12" of gravel is this; comes in 60mm, 80mm and 100mm sizes.
View attachment 137831

I used the unperforated type of drain tile/pipe and cut my own slits, so yes, it can work. I was following guidelines by a pond professional based in Georgia and I was glad I found his write-up nigh on 10 years ago. I also included a cleanout, something wide enough to get a pump into and sloped the bog+bottom to a low point, where the cleanout sat, ready in case I need it.