Question About Water Exit In Upflow Bog

[drjay9051]

I started this new thread about my bog project so it would hopefully garner some attention .

With my currently operating bog i used a plastic stock tank. Typical construction with pipes, gravel etc. The water exits at the top via a PVC pipe which exits at the top via a Uniseal.

Above the exit pipe I have about 12 inches of stock tank wall to allow for rise in water level due to roots,clog etc.

Here is my quandary:
In my new bog since I am using railroad ties to build the bog I could of course cut a groove at the top tie to allow water to spill over into the pond. However this does not allow for leaving a foot or so about the surface should I need it.

Clearly I cannot use a Uniseal or bulkhead fitting so what to do?

I thought that if I simply had a PVC pipe sitting at the top of the water/gravel interface and over the top via 2 90 degree bends the water would rise up the pipe due to hydrostatic pressure and flow through said pipe back to pond. However as I envision this wouldn't the water rise in the entire bog and spill over the sides or is there some law of fluid mechanics which states that the water will rise more quickly in a narrow pipe due to pressure and problem solved?

Everybody seems to leave a foot or so of wiggle room at the top above the gravel. How do you accomplish this with material which will not accept a bulkhead or Uniseal? Inquiring minds want to know.

I hope this question makes sense to somebody

 

[GBBUDD]

Clearly I cannot use a Uniseal or bulkhead fitting so what to do?

Stop the idea of using a barrel they don't exactly add to the property. Learn how to build a bog using a liner. you won't be sorry you did

 

[Lisak1]

I think he's replacing the tank bog @GBBUDD with a lined bog built with railroad ties.

@drjay9051 - where have you heard to leave a foot above the water line? I think what you've read is to leave a foot of EXTRA LINER to allow for settling in a lined bog. You won't ever have that much space above the waterline as you need the water to be able to exit the bog and flow back into the pond somehow.

In short - I don't think your pipe idea will work, nor will the whole set up be visually appealing. A waterfall or weir out of a bog where all the plumbing is invisible is the goal. Function plus beauty.

 

[drjay9051]

Stop the idea of using a barrel they don't exactly add to the property. Learn how to build a bog using a liner. you won't be sorry you did

I am building a bog with liner! Not sure what you are reffering to?

Bog is 16x4 with liner!!

 

[drjay9051]

I think he's replacing the tank bog @GBBUDD with a lined bog built with railroad ties.

@drjay9051 - where have you heard to leave a foot above the water line? I think what you've read is to leave a foot of EXTRA LINER to allow for settling in a lined bog. You won't ever have that much space above the waterline as you need the water to be able to exit the bog and flow back into the pond somehow.

In short - I don't think your pipe idea will work, nor will the whole set up be visually appealing. A waterfall or weir out of a bog where all the plumbing is invisible is the goal. Function plus beauty.

Per Addy1 bog building:
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.

Also numerous other posts all say to have "extra" bog wall,

 

[GBBUDD]

yes sides should be a minimum of 6 inches higher than water level when you have an appropriate sized weir.

when i see a barrel bog i guess i stop reading, the small ponds 300 gallon etc i have no experience with , i do with aquariums but not ponds so i kinda tune out, to be honest.

 

[Mmathis]

OK, I will admit that I can’t picture things well, so maybe I am misunderstanding. When I read your description I had trouble envisioning where the PVC pipe would go and how it would interact with the pond and bog. Can you, maybe draw a little picture?

 

[Lisak1]

Agree that six inches is good - but you said a foot with no waterfall outlet. Total different animal.

 

[drjay9051]

OK, I will admit that I can’t picture things well, so maybe I am misunderstanding. When I read your description I had trouble envisioning where the PVC pipe would go and how it would interact with the pond and bog. Can you, maybe draw a little picture?

Here are a couple of pics of my existing bog. Pretty standard. As you can see the exit p;ipe is plumbed via a uniseal. The poor drawing is a side view of my bog in progress. Since it is wood I cannot use a bulkhead fitting or Uniseal.

The PVC pipe extending over the top was my thought. Maybe the water will rise in the pvc outflow pipe before it overflows the sides and return to pond via the pipe.

I do not know much about fluid mechanics.

If it will overflow the sides I will need to notch out a weir and have a small waterfall as a return. Does this clear it up foryou?

 

[GBBUDD]

I did go with close to a foot on my rebuild of the bog but that was so i could do no water over the gravel or if I wanted to try 6 inches of water over the same gravel . This also added 7 inches onto the waterfall im about a 3.5 foot drop now but my water bounces on the way down just a little

Since it is wood I cannot use a bulkhead fitting or Uniseal.

But you can use a bulked you support the pipe make sure it can not move and support the liner just outside of the nut by an inch all the way around.
I tried similar with my aquarium days and air developed in the u shape of the fitting and actualy stored the syphpon.

Also a single pipe on the way out of the bog may have enough volume but once the plants get going they can easily block the pipe. We have seen people mention this happening time and again.

The hard part is getting anything to adhere to the barrel being plastic and constantly reaching oils nothing like to stick to it a compression from like a pre-made weir is needed where it can be bolted on and silicone or epdm is sandwiched by bolts squeezing it not gluing.
Plastic welding may work i never tried

 

[mrsclem]

You need to notch the top timber just enough to fit the pipe and then use a seal where the pipe goes thru the liner.

 

[drjay9051]

I did go with close to a foot on my rebuild of the bog but that was so i could do no water over the gravel or if I wanted to try 6 inches of water over the same gravel . This also added 7 inches onto the waterfall im about a 3.5 foot drop now but my water bounces on the way down just a little
But you can use a bulked you support the pipe make sure it can not move and support the liner just outside of the nut by an inch all the way around.
I tried similar with my aquarium days and air developed in the u shape of the fitting and actualy stored the syphpon.

Also a single pipe on the way out of the bog may have enough volume but once the plants get going they can easily block the pipe. We have seen people mention this happening time and again.View attachment 167768View attachment 167767

The hard part is getting anything to adhere to the barrel being plastic and constantly reaching oils nothing like to stick to it a compression from like a pre-made weir is needed where it can be bolted on and silicone or epdm is sandwiched by bolts squeezing it not gluing.
Plastic welding may work i never tried

There is no barrel!

 

[drjay9051]

If you look at my poor drawing above I would think the idea of using a PVC pipd rather than a weir would work. Granted, if I just let the bog fill it would likely overflow the sides however if I got a siphon going in the PVC I see no issue.

As long as the PVC return is wide enough and the inlet flow rate is low enough i think that would work. A simple ball valve on the inlet would allow me to fine tune the flow rate.

Thoughts?

 

[Mmathis]

Can you raise the overall level/height of the bog so that it is taller than the pond and returns to the pond by gravity?

 

[drjay9051]

Can you raise the overall level/height of the bog so that it is taller than the pond and returns to the pond by gravity?

It is above pond level.
What I am trying to solve is how best have water exit at top of the bog.
Pipe vs weir (waterfall))
Looks like a weir would be the best bet.
As Mrsclem suggested notch out for a weir.
I am trying to figure how best to secure liner at the weir as I am dealing with wood.
Im thinking tuck the liner around the notched out weir and hold in place with a heavy flat stone.
I cannot glue the liner to the notch out with something like Luquid Nails, can I ?
The wood is old railroad tie not dimensional pressure treated lumber. I do not think an adhesive will work.
I suppose I could secure the liner with small screws with washers (gaskets) but concerned about possible leak around screws.

Weir will be at a height of about
20 inches. Not a dramatic waterfall but it will do it's job.