New Koi Pond Depth


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I'm building a new Concrete Koi pond approximately 22 feet by 18 feet. Initially we were planning a 5 feet deep pond, but we have hit water table at about 4 feet depth. We are now thinking about four feet deep instead of five feet. We are in South Eastern Connecticut near Long Island sound and so winters are not super harsh. Pond will have a large volume of about 12,000 gallons.

Any thoughts on how important it is to get to five feet depth?
 
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brokensword

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it's not, especially if you have milder winters. Even 3 feet would have been fine. Better to have more surface area (for aeration purposes) than super depth. You're good to go.
 

Jhn

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I'm building a new Concrete Koi pond approximately 22 feet by 18 feet. Initially we were planning a 5 feet deep pond, but we have hit water table at about 4 feet depth. We are now thinking about four feet deep instead of five feet. We are in South Eastern Connecticut near Long Island sound and so winters are not super harsh. Pond will have a large volume of about 12,000 gallons.

Any thoughts on how important it is to get to five feet depth?
It’s not that important, many on here keep koi in ponds less than 5’ deep in harsher climates than yours and they do fine. My pond is 4’ deep and have had it ice over pretty thick in The past.
 
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My pond is in Connecticut as well and funny part is i to am 12000 . The link is below this post in blue.. I originally wanted 8 feet and very glad that plan failed. The pond in now right at 6 foot and it can be some work trying to get leaves out of the bottom of a deep pond 4 feet on the other hand isn't so hard to get leaves out of. But I will say this a lot of the Brits seem to prefer deeper but most seem to compromise at a lesser depth as well. There are proven methods to building on high water table . Its really nothing g too crazy . Either way if doing a main drain code last I checked required 2 on the same line so no one could get stuck by the suction.
As to the water table a simple open pipe from below the pond thats unobstructed and water can flow to easily will take the path of least resistance. The other trick that they do is to construct a pressure plug that way if tge water didn't go up tge pipes due to a clog tge plug would blow instead of lifting the pond .
 
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Welcome @kaycien !

Mind if I ask why concrete? Here in the midwest a concrete pond would just be a recipe for lots of cracking and frustration with all the heaving from frost. Are you planning for this to be a dedicated koi pond - no plants, just fish and water?

And many many ponds here in the Chicago area are only two feet deep and fish do just fine in our cold winters. The ice and snow on a pond are actually good insulation from the cold.
 
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My pond is in Connecticut as well and funny part is i to am 12000 . The link is below this post in blue.. I originally wanted 8 feet and very glad that plan failed. The pond in now right at 6 foot and it can be some work trying to get leaves out of the bottom of a deep pond 4 feet on the other hand isn't so hard to get leaves out of. But I will say this a lot of the Brits seem to prefer deeper but most seem to compromise at a lesser depth as well. There are proven methods to building on high water table . Its really nothing g too crazy . Either way if doing a main drain code last I checked required 2 on the same line so no one could get stuck by the suction.
As to the water table a simple open pipe from below the pond thats unobstructed and water can flow to easily will take the path of least resistance. The other trick that they do is to construct a pressure plug that way if tge water didn't go up tge pipes due to a clog tge plug would blow instead of lifting the pond .
Thank you for sharing your thoughts and great to hear from a fellow CT native! I watched your pond video and your bog pond looks awesome. Could you provide some clarity on the following -
1. Did you mention if I did a bottom drain / bottom return, I will need two of those instead of one?
2. You mentioned simple open pipe. Unfortunately, at four feet depth, I'm pretty much at sea level so not sure where I can drain. Are there other options?
3. Can you tell me more about the pressure plug? Are they lined next to pond? How many of them?
 
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Welcome @kaycien !

Mind if I ask why concrete? Here in the midwest a concrete pond would just be a recipe for lots of cracking and frustration with all the heaving from frost. Are you planning for this to be a dedicated koi pond - no plants, just fish and water?

And many many ponds here in the Chicago area are only two feet deep and fish do just fine in our cold winters. The ice and snow on a pond are actually good insulation from the cold.
The pond will be at the bottom of a patio and the steps from the patio will traverse through the pond as floating steps anchored via sonotubes and this is why we will have to build a concrete pond.
This is a dedicated Koi pond and so no plants. I do have another 600 gallon pond which is only two feet deep. We have several gold fish that have survived in this pond. The new pond is a Koi pond and not goldfish. I'm sure that at 4 feet, the Koi will survive the winter but I read in some forums that the Koi fish need vertical space as well for better growth (growing larger Koi).
 

addy1

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Welcome to the forum!

That sounds like a great build, looking forward to following along.
 
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I've heard that vertical space theory, but koi are river fish so it would seem they may prefer swimming in a current versus up and down. I've never asked them, though, so that's just a guess! ;)
 

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I have found that koi do better if they have deep water as well as room to swim. Japanese koi are raised in mud ponds that are fairly deep. They do enjoy the current from moving water.
 
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I'm in northeastern PA, zone 6a.
The deepest part of my pond is 3 feet.
I have some tremendous koi, so don't worry about 4 feet preventing your koi from getting large.

I think feeding them more often is a bigger factor in their growth.

I was told once by a knowledgeable guy that the fish excrete pheromones and if you do some water changes it dilutes the pheromones and helps your fish to grow larger.

That being said, I have some koi that are absolutely huge, over 24 inches with serious girth, and some of them (the same age) that never really got that big. I know the females are usually larger.
 
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That being said, I have some koi that are absolutely huge, over 24 inches with serious girth, and some of them (the same age) that never really got that big. I know the females are usually larger.
Genetics plays a part in growth as well. We had the same experience with our koi - same feed, same amount of time. Some were enormous while a few stayed in the 14-16 inch range.
 
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Thank you. We might be able to go down to 5 feet depth. However, based on the comments I'm seeing here, it appears we are better off at four feet for the following reasons -
1. Our pond will have a large volume (about 12,000 - 15,000 gallons) irrespective of four or five feet. Volume is more important than depth per se. We are able to make the pond surface larger if we decide to do four feet instead of five feet.
2. Four or five feet does not matter to Koi fish size
3. We are in Zone 7A, so anything over 3 feet, is ample for winter freeze
4. Four feet pond is easier to clean-up (bottom debris) than a five feet pond.

Anyone wants to chime in about going up to five feet rather than staying four feet?
 

brokensword

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Thank you. We might be able to go down to 5 feet depth. However, based on the comments I'm seeing here, it appears we are better off at four feet for the following reasons -
1. Our pond will have a large volume (about 12,000 - 15,000 gallons) irrespective of four or five feet. Volume is more important than depth per se. We are able to make the pond surface larger if we decide to do four feet instead of five feet.
2. Four or five feet does not matter to Koi fish size
3. We are in Zone 7A, so anything over 3 feet, is ample for winter freeze
4. Four feet pond is easier to clean-up (bottom debris) than a five feet pond.

Anyone wants to chime in about going up to five feet rather than staying four feet?
the only advantage would be you get more exercise re digging, imo.
 
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