Above ground build

[Crazyshot97]

So...

Total and complete newb here, I barely know any terminology so excuse my lack of knowledge and silly questions. This summer I plan to have built my first pond, and I want to make sure I don't regret it.

I've seen a ton of design ideas for above ground ponds. I really cant dig as my backyard is full of large maple trees. I want to build something that is structurally sound and will not bow/rot in the winters and summers here in New York.

I've seen concrete block ponds, ponds using 6x6's as the frame, even ponds with just a wood skeleton and plywood on the outside.

I really have no idea where to start. How much reinforcement does something like a pond made of 6x6's require? How about one with concrete blocks? I'd really rather not fill the whole thing with cement and rebar, does using a liner eliminate the need for this? What about ground freezing and thawing, would it be necessary to pour a concrete base, or "footing" (I think) to support the bottom? I would like to make this pond an L shape, 8 feet long on the long part and 4 feet long on the end.

Any help at all would be greatly appreciated. Really clueless, sorry for the bad questions!

 

[Crazyshot97]

Oh, and around 3.5 feet tall/deep would be sufficient for koi additions eventually? How does that factor in to support necessary

 

[j.w]

Koi need a big pond, about 1000 gals per koi. Go bigger or put in Shubunkins or other pretty types of goldfish.

 

[Crazyshot97]

Koi need a big pond, about 1000 gals per koi. Go bigger or put in Shubunkins or other pretty types of goldfish.

Okay, that’s good to know, I wasn’t sure how many gallons those dimensions would yield. Any input on construction? I’m thinking 6x6’s stacked up and crossed over on the corners. Then at the crossovers using large bolts to secure them together. Possibly additional corner braces? I’m worried about the weight of the water pushing outward and the weight of the water on the ground. Would a cement or gravel base make for a more stable footing than just dirt?

 

[j.w]

I've never built an above the ground pond so can't help there. Others here have and hopefully they will chime in soon for ya. Or you can do a search on this forum for above ground pond. Look through these and maybe you can find what you are wanting to know. https://www.gardenpondforum.com/search/11858/?q=Above+Ground+pond&o=date

 

[mrsclem]

The 6x6s should be good, doubt they would bow out. I have a 10x10 above ground pond that we built 10 years ago. I wish now I would have dug down. 2x12s- 4x4 posts every 2 feet, set 3 foot deep. Everything lag bolted with 1/2" lag bolts. The ground around the pond has shifted and we are now facing the sides bowing out to the point we fear collapse.

 

[Jhn]

I would use 6”x6” stacked and interlocked as you suggested. Besides pinning the corners, I would drill holes every couple feet the length and width of the 6x6 as you stack each one then pin it down with rebar. Doing it like this will not require reinforcement, as long as your ground is decent. As for putting something under the base of the pond, that depends on your ground, I never did and have had no issues with shifting or heaving. Lastly make sure any lumber you use is rated for ground contact otherwise it will rot quickly.

I have built 2 ponds using this method and have had no issues with them. My most recent pond build is as mrsclem suggested, I dug down about 18-20” and raised the pond about 20” above ground.

 

[GBBUDD]

Solid construction noted above. my concern would be freezing are you up toward buffalo or are you on long island as you know BIG difference

 

[Crazyshot97]

I would use 6”x6” stacked and interlocked as you suggested. Besides pinning the corners, I would drill holes every couple feet the length and width of the 6x6 as you stack each one then pin it down with rebar. Doing it like this will not require reinforcement, as long as your ground is decent. As for putting something under the base of the pond, that depends on your ground, I never did and have had no issues with shifting or heaving. Lastly make sure any lumber you use is rated for ground contact otherwise it will rot quickly.

I have built 2 ponds using this method and have had no issues with them. My most recent pond build is as mrsclem suggested, I dug down about 18-20” and raised the pond about 20” above ground.

Solid construction noted above. my concern would be freezing are you up toward buffalo or are you on long island as you know BIG difference

That really seems like a very sturdy idea. I doubt there would be any bowing at all with the rebar through the middle too. My ground is mostly clay, I’m thinking maybe it’s a good idea to dig maybe 6 inches into the ground and lay down some gravel just in case, I know nothing about how good my ground is. I do know that clay holds a lot of water though.

And luckily I’m on Long Island. Not much freezing going on here lately, but we definitely catch an odd day where it’s 10 degrees... or God forbid 4 feet of snow

 

[Crazyshot97]

The 6x6s should be good, doubt they would bow out. I have a 10x10 above ground pond that we built 10 years ago. I wish now I would have dug down. 2x12s- 4x4 posts every 2 feet, set 3 foot deep. Everything lag bolted with 1/2" lag bolts. The ground around the pond has shifted and we are now facing the sides bowing out to the point we fear collapse.

If you had dug down, do you think you would have submerged the entire pond? Or dug enough to put in a reinforced base? Something like concrete or gravel. Any idea if that might have eliminated the problem you’re facing?

 

[mrsclem]

If you had dug down, do you think you would have submerged the entire pond? Or dug enough to put in a reinforced base? Something like concrete or gravel. Any idea if that might have eliminated the problem you’re facing?

Our entire property was trees when we had the house built so tree roots have been a big issue. Add to that the slope of the property and distance from house. Our soil is a mix of clay and sand.Took years to get a lawn going and in the mean time, the sand all washed downhill. We continue to get the hillside shifting behind the house. The front of the pond is 3 feet down but the back side is ground level. Everything was good till 2 years ago, groundhogs tunneled into hillside behind the retaining wall and now every time we get heavy rain the area around the ponds is flooded.

 

[GBBUDD]

To be honest with you i would dig down a good 18 to 24 inches it will help keep the water warmer at the bottom of the pond on those cold days. and you wont have to worry about bowing as half the pond would be underwater and you could see the fish from a chair. BUT clay is WHAT YOU WOULD USE IF YOU WANTED TO BUILD A NATURAL POND . it allows some saturation then it wont except any more . so in one way its great in one way its bad . and bad is you need to make a way for the water to find a way out from below the pond or you could end up with a huge bubble from below pushing the liner up. It only takes a pipe or hose water will take the path of least resistance. stone can work short term but will clog evenyualy '

 

[Crazyshot97]

To be honest with you i would dig down a good 18 to 24 inches it will help keep the water warmer at the bottom of the pond on those cold days. and you wont have to worry about bowing as half the pond would be underwater and you could see the fish from a chair. BUT clay is WHAT YOU WOULD USE IF YOU WANTED TO BUILD A NATURAL POND . it allows some saturation then it wont except any more . so in one way its great in one way its bad . and bad is you need to make a way for the water to find a way out from below the pond or you could end up with a huge bubble from below pushing the liner up. It only takes a pipe or hose water will take the path of least resistance. stone can work short term but will clog evenyualy '

Interesting. Where would one direct a pipe diverting water away from the underside of the pond?

 

[GBBUDD]

Lowest part of the build or if almost flat have the pipe lead away from the pond to a garden bed or something but beware of maples they can clog a pipe up fast