A garden pond with a cascading waterfall can be an interesting addition to a hilly landscape. The cascading water provides an inviting place for birds and other wildlife to visit, while at the same time the white noise of the rushing water provides an added dimension of sound to the garden landscape. Best of all, the hillside provides a natural support for adding a waterfall to your pool.
Drive a garden stake into the ground with a mallet at each endpoint where you will lay your first row of landscaping bricks. Tie a string between the two stakes to act as a guide line for your wall.
Excavate a place in the hill to be the foundation for your wall using a shovel. Check that the surface is flat by measuring it's depth against the string. For a steep slope, you may need to construct your terrace foundation in several levels using a stair step method.
Lay in your first layer of stones and tamp them in place using the rubber mallet. Each stone should be flush with the next, and all stones should be level. Then lay your end stones for the second layer. These stones should be half as long as the stones that you use for your first row, so that your second layer of stones is staggered from the first. Fill in the rest of the stones for your second row. As you build your terrace, move the string and use it to check that each course is level.
Fit a sheet of landscaping fabric against the back side of the stone terrace wall to prevent dirt from washing into the cracks in the wall.
Place a layer of gravel to a depth of 2 inches against the backside of the terrace. Lay the drain pipe against the terrace, and cover with another 2 inches of gravel. Cover the gravel with sand to a depth of 4 inches.
Dig out the dirt from the surface of the hillside to flatten it into a terrace and carve out a place for your preformed pond liner. Backfill this extra dirt into the pocket created between the terrace wall and the hillside.
When your pond site has been quarried, pour sand into the site and smooth out the sides. Then place your preformed pond liner into the excavated hole. Fill the pond with water to anchor it in place.
Dig a trench into the side of the hill to serve as the base for your waterfall. Line the trench with sand, and lay pump tubing throughout the length of the trench.
Cover the trench with your preformed waterfall liner, making sure that the liner overlaps the edge of the pond. Cover the sides of the liner and the pond with river rocks to soften the line between the two. Fill the waterfall with pea-sized gravel and river rocks to create the appearance of a realistic waterfall.
Attach the tubing at the pond end to the outflow valve of the pump. Place the pump under the surface of your pond's water. Hide the mouth of the tubing where water will flow out at the top of your waterfall with rocks.
Put in marginal plants such as bulrushes in pots in your pond and plantain lilies in the dirt outside your pond and waterfall.