Pond Boss Forums POND CONSTRUCTION Selecting a site Concrete pond construction

Hello fellow pond enthusiasts,

I'm in the process of constructing a pond and would love to get some advice from those with experience in concrete pond construction. The pond has been excavated, revealing a sloping bedrock at the bottom. The sides are steep, almost vertical, and part of the pond structure is above ground, reinforced externally with a thick layer of soil and stone.

I plan to use concrete blocks for the sides, but I want to maintain the natural slope of the bedrock. To do this, I'll need to create a level base or foundation around the sides on the bedrock before setting the blocks. What would be the best approach for building the foundation? Could a circular slab reinforced with rebar work? What would be the best waterproofing agent or coating to apply to the concrete to prevent water leakage and protect aquatic life from the alkali content of the cement?

I'm aiming for a durable and eco-friendly solution that ensures the health of the pond's ecosystem. Any tips, product recommendations, or construction techniques would be greatly appreciated. I know that it would be easier to just use a pond liner but I am optíng not to.

I just responded in your old thread, but now I see you have gone to Plan B!

Are the sides of the pond also cut down into bedrock, or are they unconsolidated material? Concrete block walls are not great at resisting lateral forces if there is water-saturated, unconsolidated material on the outside of the wall is trying to push into the pond.

Of course, the water in the pond will somewhat help resist the external lateral force. Will your pond usually remain full, or will the water level cycle up and down?

Is there any chance that the bedrock itself could be a seal for your pond? Even if there are natural fractures or a visible joint pattern in the bedrock, sometimes those cracks can be "blind", and not connect to any significant additional void spaces.

Can you drill into the bedrock with a hammer drill and a masonry bit? If so, rebar drilled into the bedrock that also extends up into your concrete pours would make an exceedingly strong foundation.

There are several "construction guys" in the forum. Hopefully some of them also have some expertise in concrete foundations to answer your specific questions.

Good luck on finishing your pond utilizing Plan B!