Frozen bog

[Lisak1]

We only run one pump on our pond that stays on all winter. The bog appears to be frozen but the water just keeps flowing. The few times we've had to shut down the pump, we were careful to make sure that water stayed in the bog. The plants can handle being frozen in the ice, but they don't like being exposed to the air and frozen - learned that from experience! We have a ball valve we can shut that keeps the water from back flowing from the bog back to the pump.

 

[Mackie Byars]

This freezing weather brings more bog questions! This is my first winter and I’m afraid I’m not too smart when it comes to frozen bogs. I unplugged the pump before the freeze. The water drained down into the pea gravel and froze. Now that the weather is slightly better, I’m not seeing any water in the bog. Is this normal, did the water drain back into the pond? The pond looks full, so did the the extra water just go over a low edge? When do I plug in the pump again, and put in more bog water. We have warming weather now. Forecast is for upper 40’s and low 50’s. I’ll be glad when I start feeling better about the bog. All I do is run back and forth to the pond checking for water, ice ,or miracles! I am ready for spring!

 

[Lisak1]

@Mackie Byars we'd need to see a picture or get a description of your whole bog and pond set up to answer any questions. Everyone's situation is completely different. Your bog COULD have drained back into the pond depending on how it's constructed. If that's the case, turning the pump back on should refill it. But it may be frozen below the surface. Where's your plumbing to the bog? Is it buried or exposed? Why did you turn it off in the first place?

 

[Mackie Byars]

The hose connected to the pump comes over the bog wall and connects to the pvc pipes under all the pea gravel. There’s about 3 feet of hose that’s exposed.

 

[Lisak1]

So that's a concern. If water stays in that hose when you shut down the pump, it could freeze and crack the hose. So you need to know what happens when the pump turns off.

Did you build this pond and bog?

 

[Mackie Byars]

Also Lisak1, the woman at the garden center where I purchased the pump said to turn it off anytime it got to 18 degrees. I was afraid the pump would freeze up. The pond never froze much so I guess the other pump to the bog would have been fine too.

 

[Lisak1]

The magical 18 degrees, huh? That number literally means nothing without knowing your full pond set up. Exposed plumbing, where's the pump, how deep is the pond, how much water volume, how is the bog constructed... I could go on and on. If you want useful answers we need real details on your particular pond.

As a sidebar - people at garden centers are not pond people even though they sell pond stuff. If they build ponds, if they have a pond - cool. Otherwise they are just another retailer selling you a product that they probably know little to nothing about. Or a high school kid who needed a summer job.

 

[poconojoe]

When you turn off your pump feeding the bog, the water, due to a vacuum, will all get sucked back into the pond and empty the bog.

You can see this in action if you turn off your pump and pull it out of the water. You will see the water reverse flow, coming out of the pump's intake.

To prevent this you need some sort of a vacuum break. The easiest way is to shut the pump and open the pipe at its highest point to break the vacuum. You can use a union in that section of the PVC pipe. Turn the pump off and open the union to break the vacuum.

Some people have installed a check valve or a dedicated vacuum break to prevent this, but those devices can fail due to clogging.
Some people drill a (permanent) small hole (within the bog) in the pipe feeding the bog. This will break the vacuum without any input from you.

 

[Mackie Byars]

Thanks for all the expert advice! I plugged in the pump and the bog is flowing fine. The weather is going to be nice this week, so hopefully I can deal with the issues.

 

[poconojoe]

Thanks for all the expert advice! I plugged in the pump and the bog is flowing fine. The weather is going to be nice this week, so hopefully I can deal with the issues.

If you decide to shut it down when it gets cold again, try to break the vacuum immediately after you shut the pump off. This way the water in your bog doesn't reverse flow and the bog won't drain down.

If you have hardy plants in the bog, they need the water even if it freezes solid, or they will dry out and die.