ccoombs1,

Thanks for the follow up. This is pretty much what I figured, but didn't know for sure. Since I already have the concrete blocks I'm going to go on as planned with the blocks along with some concrete and rebar. It won't be cheap, but it should last forever.

Thanks again,
Don

My pond is 18" above ground and 18" below and I'm using the interlocking concrete blocks with no cement. I have noticed the long straight side has bowed in the middle about 3" in 5 years. Here is a picture {{gwi:182211}}

Our pond is on a slope and the back wall is curved- 30 feet long and up to 40 inches tall.

We built a footer and did concrete blocks, vertical rebar and horizontal rebar.

We filled all the blocks with concrete.

For good measure, we did concrete block pilasters behind the wall. That was probably overkill.

We back filled dirt against the bottom of the wall on the pond side before we placed the liner.

The deepest part of our pond is about 4.5 feet in the middle.
My dad is a structural engineer and helped us design it.

HTH
Here is a pic of while we were constructing the wall. It took us a whole summer of evening and weekends.At the time of the photo, we had not back filled the wall yet.
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Here is it after we finished.
Unfortunately, this photo does not show all of the back area.
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WOW! Great pics everyone! I love all the great advice people are willing to share here...I think it's better than most the "pond" builders that want you to hire them!

lsst,

I'll second the WOW!! To be honest I hadn't thought of adding horizontal rebar. I guess I figured that the combo of vertical rebar and filling the blocks with concrete would make a rigid enough structure. The combo of horizontal and vertical rebar seems like the best way to go.

Thanks to everyone for their help,
Don

My top pond is cinder blocks, concrete, and rebar. Fairly cheap. BUT I've got to say that I wouldn't do it that way again. I folded the liner where the water level is and did not realize that I would be able to see the liner. If I had it to do over again I would have done it differently- preferably would have found another way to water proof it.

You won't need horizontal rebar at every course. I'd do the first course that is above ground level and another on the top. And you don't have to buy the blocks that are already notched out. Get a masonry blade for your circular saw and make 6 cuts in the block, so you can create a trough for the rebar to sit in. Once the cuts are made, just tap it with a hammer and the chuck falls out, leaving a nice grove in the top of the blocks. I have horizontal rebar in about every 3rd course and at the top, and vertical rebar and concrete in every hole. It would take a tank to knock this thing down!

{{gwi:206430}}

{{gwi:206433}}

{{gwi:206436}}

Man, I love this forum!

ccoombs1, it looks like some blocks have mortar and some don't. Since I would be filling up the inside with concrete and using rebar, do you think I could get away without using mortar IF I coat the block with something like stucco that will prevent water from getting in any cracks (to prevent water from freezing and crackng seams in the winter)?

Thanks to everyone,
Don

Here is a link that might be useful: Currently in bloom

None of them have any mortar. Mortar adds no strength against outward forces anyway, so it's not needed. I just dry stacked them and filled them all with concrete.

Kalevi - That's exactly what I want to do in my new house with pavers! I love it! I'm moving from a large yard with 2, 1000 gal ponds and assorted other water features to a much smaller yard. I certainly still will want a pond and plan one like yours. Thinking about 18" below ground and 12" to 18" above. Same shape because I will back it up to a garage on the long side. A couple of questions:
Does the paverwork go all the way down below ground level or can I dig down and line the below ground portion and start the paverwork at ground level? What would be stronger?
ANyone else who has done something like this, feel free to join the discussion!

I left a plant shelf at grade level. I dug a small trench that I filled with stone dust for the blocks to sit on so the blocks are at grade level. Then I had about a 1'wide plant shelf sticking out after which I dug down to 18' deep. I laid all of the blocks except the top row, then put in the liner and laid the top row on and then trimmed. My pond came out to about 1100 gallons. It is a 7' radius half-circle.

Terrific! Love the plant shelf idea too. How deep did you dig for the crushed stone base? You're colder than I am. Any problem with heaving pavers with the rock base?

Pat: The crushed stone go about 4" deep and 1" wider than the blocks on both sides. No heaving. The pond does not freeze all the way down so I can winter my fish outside and the plants which I sink into the deep part for winter.

Perfect! Thanks so much for the info. I have been scouring sites to find the right design and materials to do just what you did. Glad to know it doesn't freeze solid tho' @ 30" it shouldn't here either. As much as I am going to miss my 15 year old ponds here, I am excited about a new start, especially with your info. Thanks, again.

This works OK for a water height of 18" above grade. I would go with some reinforcement if you want to go much higher with the water level above grade.

I am building a swimming pool in the beach. I will use a solar pump to bring the water from the ocean. I was going to use 8" blocks and make it about 4 to 5 feet deep. With the water pressure inside and the sand and water pressure outside, would rebar vertical and horizontal and filling the blocks with concrete be good enough