Hey Everyone,
I’m working on building a 1 acre swimming pond we are in an area with heavy clay so we are doing a natural bottom with no problems there.

I want to and sand to the bottom to help keep the water clear and make it nicer for swimming. I have read that the sand will just disappear into the clay. I was considering just putting down a heavy visqueen sheeting between the clay and sand to help provide support for the sand. Any thoughts or ideas on how to do this better?

I'm wanting to do a small section of sand along the side for a beach look. I was told it will wash away and need to be replace a lot. Seems like it could be a lot of work. Not sure if it will help clear it up or not. I'm curious on how it turns out for ya. WELCOME to the forum. Have ya started digging yet.

I did not do the sand so can't comment on it. But I did do a shallow swimming area for our grandkids when they were small. It turned into a filamentous algae nightmare. I ended up digging it out deeper best I could with a back hoe.

Thing of it is, the small kids hardly used it anyway. We have a nice dock extending out into the pond with a ladder to get back up. They always ran and jumped off the dock.

My vote would be forget the swimming beach and instead spend the money on a good dock to swim from. But it is your pond, your dream so by all means make it the way you want it. Just my experience.

Another bit of experience: docks are easier to build before the pond fills with water.

I would second that. we always use a dock and a float dock for swimming, and rarely touch the bottom. Invest in a nice ladder, and even better, build a floating dock that goes up and down with the water level unless you are certain your pond will always stay level.

The sand will slide off the plastic into the depths unless it is turned up at the bottom to form a barrier. At any rate, the sand will become mixed with clay anyway unless your pond stays perfectly clear. Any stirring of the bottom clay will allow some clay to settle on the sand. A floating dock is better, so that the bottom is not disturbed. Lots of undesirable things are trapped in bottom muck, so best not to stir it up.

Generally bottom muck develops about 1" of depth on the bottom each year regardless of the composition of the bottom. Heavy leaf inputs significantly increases the annual accumulation. So the sand bottom will accumulate muck as mostly dead organics on top of it over time.

Bottom muck comes from land based organic materials that blow into or plants that grow in the pond. Ponds tend to be productive habitats where all sorts of things grow in them from microscopic phytoplankton to filamenteous algae and weeds. All these plants have life spans from days to months and they then die and sink to the bottom.

Less bottom muck accumulation occurs each year in very low nutrient, very clear water. Watersheds contribute a large percentage of the nutrients. And even in very clear water lakes, submerged plants grow on the bottom where ever light reaches the bottom. Thus the clearer the water the more of the bottom that tends to develop some sort of plant growth.