Wintering frigid temps in GA

[addy1]

where there's a good ice cap on the pond, I've seen the ground temps will bring the water up as high as 40 degrees.

my pond is staying right at 41F, solid ice cover, pond breather working, temps in the single digits.

 

[SE18]

without fish to worry about, my cement aqueduct is drained so it won't expansion crack. I do need to add a snowplow to the train that goes around the edge though (photo taken a couple days ago). The canal stays full of water year round so frogs have a place to stay in winter. The canal is made of concrete/pvc liner/concrete sandwich so any cracking is of no concern

 

[Lisak1]

I've never seen this super-chilling effect that you speak of

Dave knows I've questioned this one before. Perhaps it's a difference between an in-ground pond and an above-ground pond. The ground surrounding an in-ground pond will keep the pond water (especially near the bottom where the fish spend the winter) warmer than the layer that freezes at the top. A pond that was exposed on all sides would not benefit from that insulating factor that the ground provides. The water that enters the pond from the waterfall is obviously (at least) above freezing, or it wouldn't be flowing. So where is the "supercooling" coming from?

I'll be the first to admit that I don't know everything and science is definitely not my thing so if I'm missing something here I'll be happy to learn! I do think pond construction and design comes into play - where your pump and lines are located, how your waterfall/streams are constructed, above ground vs in-ground, etc. Having a waterfall that ices in such a way that it re-directs water out of the pond would be a disaster. But we've run our pond all winter now for several years, and these last two have been especially brutal, but our fish have survived and thrived. We noted after last year's polar vortex that we had spring algae growth that we had never seen before - it was a bright, vibrant green before the ice was even completely off the pond. Also our fish had grown noticeably bigger over the winter months - we were pretty surprised by that one!

 

[DrCase]

I got my ponds running again today they still had about 1" of ice on them

 

[addy1]

When my bog and stream are running they chill the water big time, a lot of surface area the water flows through.

A person with a nice large pond here in Maryland ran an aerator last winter, like he had for years, every fish died in February, we hit -15. Over 150 fish bodies pulled out, they started dieing towards the end of February when the coldest weather hit. The only reason that could be come up with was super chilling. His small pond with nothing running had survivors in them, solid ice cover.

I changed from running an aerator to the pond breather, after the death of his fish. The temp of the water is warmer with the breather. My pond temp with the aerator was around 37 or so at the bottom, this year with the breather it is 41 and holding.

 

[Dave 54]

Dave knows I've questioned this one before. Perhaps it's a difference between an in-ground pond and an above-ground pond. The ground surrounding an in-ground pond will keep the pond water (especially near the bottom where the fish spend the winter) warmer than the layer that freezes at the top. A pond that was exposed on all sides would not benefit from that insulating factor that the ground provides. The water that enters the pond from the waterfall is obviously (at least) above freezing, or it wouldn't be flowing. So where is the "supercooling" coming from?

I'll be the first to admit that I don't know everything and science is definitely not my thing so if I'm missing something here I'll be happy to learn! I do think pond construction and design comes into play - where your pump and lines are located, how your waterfall/streams are constructed, above ground vs in-ground, etc. Having a waterfall that ices in such a way that it re-directs water out of the pond would be a disaster. But we've run our pond all winter now for several years, and these last two have been especially brutal, but our fish have survived and thrived. We noted after last year's polar vortex that we had spring algae growth that we had never seen before - it was a bright, vibrant green before the ice was even completely off the pond. Also our fish had grown noticeably bigger over the winter months - we were pretty surprised by that one!

Liska Val and I factored in all the exposure problems on our above ground pond using insulation to do so .
Namely 22 mm polystyreene sheets wrapped aroumd the pond then silversided bubble wrap then the whole pond was wrapped in recycled plastic loft insulation as was any pipeworkand was finally decked in.
The same can be said for our filter housing and the Policarbonate roofing sheets that cover both the filter housing and pond being our final defence against the cold .
All was thought through in the early planning stages of our build and the right materials sourced prior to the build .
Superchilling is a fact on ponds with water falls and they are recomended to be switched off in all the litrature I've read so far.

Dave

 

[Lisak1]

Superchilling is a fact on ponds with water falls

Can you explain what that actually means? I could see that adding cooler water to the pond may drop the temperature, but what does "superchilling" or "supercooling" imply? It sounds like it's much more than just causing a drop in water temperature.

 

[Dave 54]

Can you explain what that actually means? I could see that adding cooler water to the pond may drop the temperature, but what does "superchilling" or "supercooling" imply? It sounds like it's much more than just causing a drop in water temperature.

Rather than me explain it all to you Liska I'll ask Doc Johnson DVM author of Koi Health and Disease Vol 1 and the 2006 reloaded Vol 2 and Fancy Goldfish "A complete Guide to Care and Collecting", to explain the effects of your superchilling your pond from his website :-

http://www.drjohnson.com/a_article_koi_ponds_wintertime_considerations.html

I think he does a good job of putting his point forwards that you can superchill your pond by leaving your waterfall on especially during the night

Dave

 

[addy1]

When I turned off our bog and waterfalls, early this winter, the temperature of the pond went up by around 7 degrees. The constant flow of the water through the cold night air brought down the temperature of water. In the summer the constant flow of a waterfall will help keep the pond cooler, I used a 4 foot high waterfall with my Phoenix pond to keep that pond in the 85 degree range, even when our summer temps were hitting 115-120.
I have four waterfalls with this pond, great aeration for the summer, no way would I leave anything running during the winter.

 

[Dave 54]

When I turned off our bog and waterfalls, early this winter, the temperature of the pond went up by around 7 degrees. The constant flow of the water through the cold night air brought down the temperature of water. In the summer the constant flow of a waterfall will help keep the pond cooler, I used a 4 foot high waterfall with my Phoenix pond to keep that pond in the 85 degree range, even when our summer temps were hitting 115-120.
I have four waterfalls with this pond, great aeration for the summer, no way would I leave anything running during the winter.

Yes addy weve decided to run a further filter in the summer months from now on after last years record temperatures we had to suffer with, which were in the high 20's water temperature wise i will run direct into the open air, thus cooling the water somewhat.
Unlike the pond filter pipe work fixture which is situated 2ft down the side of the pond and enters directly into the pond .

Dave

 

[Lisak1]

I think he does a good job of putting his point forwards that you can superchill your pond by leaving your waterfall on

I would agree that he makes the point that he BELIEVES that I can "super cool" my pond, but he doesn't really explain what that means. I'm really looking for an explanation as to what "super cooling" means. It must be more than just lowering the pond temperature, or people would just say "you may not want to run your waterfall because you'll cool your pond water and your fish won't be happy". Instead we call it "SUPER COOL" so it sounds really scary and bad.

The author states "Again, this is a geographical phenomenon and may not apply to you." Understanding what "super cooling" is and how it works would help pond owners decide whether or not it DOES apply to them. The article also says "Temperature swings within the pond over near twenty degrees Fahrenheit are very stressful for the fish." I would agree with that, but I would contend that it takes my pond a series of very cold days for the temperature to drop by even a few degrees. Dropping it by 20 degrees over night would take an extreme change - like dropping an iceberg into the pond. (I'm being facetious, but it really does take a series of consistently cold or warm air temperatures to affect the water temperature. That I do know from my own observations.)

I think sometimes we hear things and repeat them without really understanding the how and why. I'm the kind of person who wants to know the reason why things happen. Someone claiming to have expertise in an area can still be repeating information that is incorrect. The article that you linked to Dave also says that there is no harm to your fish in banging on the ice to create a hole if you don't have time to create one slowly - would you agree with that? Now perhaps I can assume he is referring to the ice he sees on Georgia ponds that he says rarely lasts more than 48 hours, not the ice that I have on my pond that is several inches thick and lasts many, many weeks. Two totally different scenarios. Cracking through a thin sheet of ice would probably not cause any distress to my fish - hammering my way through six or eight inches of ice would be a different story. (I mention that only to illustrate my point that opinions are often presented as facts.)

 

[Dave 54]

Perhaps I should have explained it myelf and yes you are correct we do tend to take in information without understanding it.
Who am I to understand anyones pond in the US Cayman Islands or even Austria ,to be truethful I dont Liska I have a good idea about UK ponds plus the effect our weather on them only.
However I do have information that if a person knew about it they could then do something to correct it,.
So by passing on this information on via the forum it becomes useful to others
So in reality it would be irresponsible of me "not" to bring it to your attention the fact that it does happen don't you agree ?
From there as you say through your own observations take onboard what is happening or the other senario totally miss understand what it is thats happening in the pond, then suddenly think what was it Dave and Meyer said about supercooling the pond ?
Ponds with waterfalls can and do run the risk of superchilling or cooling its down to the owner to put two and two together.over this, they know their ponds ,
So by bringing it up on the forum it was remembered by your good self and commented on, so now you are making your own mind up what you should be doing, should global warming catch you out with a severe winter .
mess with your winter and this superchill came into effect on your pond just the same as I would ,


Dave .

 

[addy1]

When the guy here lost his fish, running an aerator, we went from our "normal" winter temps of the low teens to minus 15 in just a few days. That may have caused the death of the fish, the pond temp may have done a downward dive fast. The bubbling water was hitting those cold temps. He did not have a temp gauge in the water, all he knew that happened bodies started showing up soon after.

 

[Shdwdrgn]

Just to add my own theory to the super-cooling debate... Imagine if you had a high waterfall that the wind blew through, or a waterfall that cascaded down across a large pile of rocks before entering the pond. What if you had the waterfall at the top of a long shallow stream? Each of these situations could cause the water to lose heat much faster than normal. Remember that heat loss is directly related to the exposed surface area of the water -- water poured over the face of a rock in a thin sheet has a much greater exposed surface area than water pouring out of a pipe. The layout of your pond has a huge effect on how fast the water might lose heat. A deep pond with straight walls will retain heat better than a shallow pond that slopes up towards the edges. And one last factor to consider is the flow of water... You have a pocket of warmer water at the bottom of your pond, but if the water from your pumps is stirring up that water, then your fish will suffer.

In my pond, the waterfall only disturbs the top ~6" of water, so the fish laying on the bottom feel very little effect from the flow. All of my pipes are buried at least a foot, and the waterfall flows as a solid stream of water over the top ledge and straight back into the pond. There isn't a whole lot of room for heat loss, so I generally only have to run heaters for 1-2 months. I wasn't thinking of heat loss when I designed my pond, but I had to keep everything compact and I lucked out that it works well through the Winter.

@addy - I can't imagine a temperature swing of 30F would be enough to hurt the fish by itself. There must have been something else that contributed? Did that guy have a raised pond or something else that contributed to heat loss? I say this because in my area, it is very common to see temperature swings of more than 50F in just a few hours as different storms blow in. Just a couple weeks ago we had the temperature swing from 8F to 53F in 3 hours, but it barely affected my water temperature.

 

[Lisak1]

I totally get that the water flowing over the falls could conceivably be cooled by the air temperature - in fact, I'm willing to say that I am sure it is. However, is that water really THAT much colder than the water at the surface of the pond - which is in fact frozen? And, as you said, does that really affect the very deepest part of the pond where the fish obviously know the water is the warmest? And what's with the "super cooling" theory - why not just regular cooling? And could that water conceivably be WARMER than the water at the surface, since the surface water is frozen and the waterfall water is still able to flow, hence not frozen. And let's say it is colder - how MUCH colder? Cold enough that we have to give it the SUPER label? When my pond thaws, the first part that thaws is the area where water is flowing from the falls into the pond... why is that, if that water is so much colder? In fact, the first part of the pond to freeze is the area furthest away from the falls. Hmmm... (I'm pretty sure that has to do with the surface being undisturbed, but I'm just sayin'!)

Pond construction is definitely key. I think if you have a submerged pump in your pond which pulls water down to the bottom before it pumps it out you may indeed be pumping warmer water from the bottom of your pond and replacing it with cooler water from the waterfall. Our pond works a bit differently so we aren't drawing warm water from the bottom and pumping it out of the pond. Definitely something to consider in construction. But I've seen lots and lots of ponds in our climate that run all winter with submerged pumps. The biggest issue is always water diversion due to ice dams - never "super cooled" water.

See the kinds of things I ponder (haha!) in the cold months when I can't busy myself in/around the pond?