Dig out the pond to the desired depth and width. Natural clay may already exist as a thick layer under the top soil you dig out. Check the soil particles to see if your pond is on a bed of natural clay, as this will save you from having to purchase it.
Compact the clay using the tread of a backhoe. If you need to buy clay, then put down a layer of clay about 2 inches thick completely covering the bottom and sides of your pond. If you have access to livestock, a low-tech compacting alternative is to lead a horse or cow over the clay layer; its weight will compact it.
Add two to three more layers of clay, compacting each layer after it's lain. If cracks form in the clay, simply fill them with more clay. You can use Bentonite clay as a filler if you already have a natural clay bed.
Fill your pond with water, and check for leaks. If there are leaks present, let the remaining water evaporate or drain it, and add another layer of clay, making sure to firmly compact it.
Refill the pond with water, and plant marine flora on the bottom of your pond. These will slowly filter the silt particles from the water in your pond, clearing up the water.
Things You Will Need
- Natural clay
- Bentonite clay
- Fresh water marine plants
- Try to use native fresh water marine plants for the bottom of your pond.