Concrete – Building a raised wall for a pond


We are looking to build a small pond (9'x18'x6'), but we want the edge to be raised up about 8". I am thinking about using CMUs (Concrete Masonry Units) which are 8x8x16. The entire pond will be lined with an EPDM pond liner.

My question is that since some of the water will be pushing up next to the blocks, how do I figure out to engineer this so that the blocks don't push out?

  • Concrete footing?
  • Rebar in some of the blocks?
  • Rebar in all of the blocks?
  • Fill the openings of each block with concrete?

So, I have a pretty good idea of how to over engineer this, but I don't want to waste time and money though either.

If you don't have any concrete answers, but if you know where I can find this information, that would be great too.

Best Answer

Unbelievable good math for a block wall, but I think Jim is only going to have one block on the ground at the top of the pond. The liner itself is very strong, and once laid up and over the block, that block is not going anywhere. Not only would 6 inches of water have to move the block, but stretch the liner the same distance as moving the block. The most i would do is drive a few 3 foot rebar rods in the holes of the blocks and fill the holes with dirt or concrete. We have build 100 foot by 150 foot, 8 inch deep deep skating rinks out of standard concrete blocks with absolutely no extra support, just a little backfill behind the block, laid in the liner, the fire dept filled it up and nothing moved.