Rocky soil presents a challenge for any type of garden. When you are building a water garden, the challenge is magnified by the fact that the rocks are taking up space where you want your pond to be. Removing rocks can create a physical challenge, but once the rocks have been removed, the process isn't as simple as filling the remaining space with a liner and a little water.
Lay out the shape of your pond with a garden hose. Then measure the surface area of your pond with a tape measure. Double the square footage of your pond's footprint to calculate the size of pond liner sheeting and rubber underlayment.
Hammer stakes into the ground around the perimeter of your pond with a rubber mallet. Attach string to the stakes in a grid pattern to make it easier to excavate your pond.
Cut your sod with a spade and remove it in layers from the surface of your pond. Then cut a narrow shelf around the lip of your pond. This will be where you place rocks that you dig out of your pond for landscaping around the edge of the water. The liner will rest on the lip, and the rocks will anchor the liner in the shelf. The surface of the rocks should be flush with the surrounding soil.
Excavate the soil by scooping it out with a shovel. Use the grid system to determine how deeply each section of the pond should be dug in each grid square. Leave shelves around the edges of the pond for the containers of marginal plants.
Remove rocks by digging around the edge of the rock to loosen the soil, and then lifting the rock free of the pond bed. Place the rocks aside to use in landscaping.
Backfill the hollow left behind by rocks that are deeper than the pond's bottom.
Cover the floor of the pond with a 2-inch layer of play sand. Slightly wet the sand with a garden hose to help it stick together to smooth out easier.
Spread a rubber underlayment over the bed of sand. Smooth out the underlayment so that there are no wrinkles. Repeat this process with a sheet of pond liner.
Anchor the edges of the underlayment and pond liner with the rocks that you dug from your pond. Then fill the pond with water.