How to Build a Water Garden with a Waterfall on a Hillside

Determining the size and location:

You must first decide how big you want your water garden to be, and you must select the proper location. Before even thinking about excavation, you must decide if you want to use a preformed garden pond kit or a pond liner. This decision will help to determine the supplies needed and the shape of the pond hole to dig. In planning your pond size, you must decide whether or not you want it to include plants, or whether you also want to stock your pond with fish, such as Koi. You must decide if you want it to include a waterfall (an important element in my opinion). You must design your pond for the specific elements you want. If you decide to stock Koi in your pond, you will need a somewhat larger pond. In addition, you will be more limited as to the amount of aquatic plant life in your pond because Koi eat some plants. If you plan to stock Koi, you must have at least a 1000 gallon water capacity and a pond depth of three to five feet. Many typical water gardens have both aquatic plants and Goldfish. If you stock Goldfish and a variety of aquatic plants, you will need to plan for a minimum pond area depth of two feet. If you live in a colder climate, you may need more depth to keep the pond from freezing solid. Small floating heaters are available to assist in prevention of ice formation and buildup, if needed.

In selecting the proper location, be sure that you place the pond and waterfall close enough to your home that you can easily see, hear, and enjoy it. Construct your pond where runoff from rain will not flow into it possibly carrying fertilizers and debris into the pond. You should avoid positioning your pond too close to trees so that you won't have to remove leaves from it. If the lay of your lawn is a combination of level terrain and hilly terrain, you face more of a landscaping challenge than you would with a completely level terrain. If you face the challenge of landscaping a lawn that has a hillside as part of the terrain, a hillside water garden with a waterfall is the ideal solution for embellishing that problematic hilly portion of your terrain. If such is your terrain, definitely plan to construct your water garden with a waterfall on the hillside with some excavation needed. The slope of the hillside lends itself to the natural gravitational fall of the water into the pond. If you want to grow Water Lilies, your pond should be positioned to receive about four to six hours of direct sunlight.

Determining the shape and beginning excavation of the pond and waterfall:

While planning the size you want your water garden with waterfall to be, also determine the shape that you prefer. If you use a preformed garden pond, which is usually made out of fiberglass or a hard plastic, you are limited to several shapes and sizes, but the pond construction is much easier to do when following the manufacturer's instructions. A more difficult technique would be to build your water garden pond with loam or in loamy soil, a more natural solution, or to build it with concrete, a much less natural pond design that cannot be easily changed. If you are going to design the shape and size of your pond using a pond liner, rather than a preformed structure, the task is a little more difficult but allows for more creativity in design. If you intend to use a pond liner, the easiest way to configure the shape and size is to "sketch" it on the ground by laying out a rope or water hose until you get the design and size you prefer. Then measure the maximum length and width. Add the depth twice to these measurements plus a foot or two for overlap to determine the pond liner size.

Dig the water garden pond into the base of the hillside. If you are unable to position it exactly on the base of the hillside and must excavate it directly on the slope of the hillside, dig deep enough into the hill that your pond will be level and stable. Use a carpenter's level on the excavated area. Dig the pond for your water garden in the shape that you designed. Dig at least a one foot deep and one or more foot wide shelf around the perimeter of the pond. Dig the remainder of the pond with a slight slope to the end opposite the waterfall. Excavate a shallow area for a stream up the slope of the hillside where you want the waterfall to flow directly into the pond. Later in the construction you can place field stones or cut stones in this shallow excavation to create levels over which the waterfall can cascade in its pathway to the pond.

Placing and connecting the pond filter, pumps and skimmer and spreading the liner:

A ditch should be dug for the plumbing from the pond to the waterfall or external pond filter. If you use a pond skimmer, bury it to the proper level beside the pond. If you use external pumps for the skimmer, the filter, and for the waterfall, (as is pictured in the diagram), dig ditches to the external pond pumps and from the pumps to the skimmer, to the external pond filter, and to the waterfall. However, if you use submersible pumps for the pond filter, for the skimmer and for the waterfall, then you should dig the ditches from the pond where the pumps are submerged to the skimmer and up to the waterfall. Most submersible pond filters and pumps for the filter are a self contained unit. Therefore, the submersible pump would be the better choice. Using external pumps for the filter, skimmer and waterfall makes it necessary to hide the pumps among rocks and foliage so that they don't show. Use about one and a half to two inch plastic or rubber hose or tubing to connect the pumps with the other apparatuses. The size of the tubing depends upon the size of the pumps and the water volume capacity you desire. If you are using a submersible, rather than an external pump for the waterfall (recommended), run the tubing from the submerged pump up the ditch dug in the hillside to the top of the waterfall area so that the water can spill from the tubing down the waterfall path.

Now that the tasks of excavation and plumbing are done, you are ready to line the pond and waterfall excavation with pond underlayment and then position the pond liner (or preformed garden pond) into the hole excavated for the pond. Place additional pond liner up the shallow excavated waterfall area covering the ditches and tubing. Smooth out any wrinkles in the liner and place some rocks along the edges to keep it smooth and in place as you turn your attention to the next step in the process.

Edging the water garden pond and filling the pond:

Edge the water garden by arranging stone around it. Fold the pond liner up behind the stone to slightly above the water level. It may not be necessary to mortar the stone into place if the stones are large enough to be stable. If you use small stone, mortar may be necessary for stability. Then back fill with soil to hold the pond liner against the stone. Fill the pond with water to within a few inches of the top. At this point, make corrections if necessary to ensure that the pond is level. As you are filling the pond with water, smooth out any wrinkles in the liner. To create a more natural appearance, avoid just having a ring of stones around the pond. Space, stack and arrange stones randomly and in layers to make the water garden blend in better with the natural landscape. Continue randomly positioning, layering and stacking stones on top of the liner that covers the waterfall excavation and tubing. This will create a natural look and allow for a waterfall that cascades down the stones.

Adding dechlorinator and aquatic and other plant life:

At this stage, you are ready to add dechlorinator to treat the water in the pond. Also add a packaged bacteria to seed the pond filter and pond. If you are going to have Koi or Goldfish, they should be added a just few at a time over a period of several weeks to allow the bacteria to establish in your water garden.

As soon as possible after constructing the water garden, you should choose and add your aquatic plants. This is the most pleasurable portion of the project. Floating leafed and submerged plants are necessary for a healthy pond. You must include them in your selection. The most vital plant to add is Anacharis, an underwater plant that uses up the nutrients that would otherwise feed the algae. For water gardens under 25 square feet, use one bunch of Anachris for every square foot of pond surface. For water gardens of 25 to 100 square feet, use one bunch for every two square feet of surface. For ponds 100 to 300 square feet, use one bunch for every three square feet of surface. You should use one bunch for every four square feet for water gardens over 400 square feet in size. Hardy Lilies, such as the fragrant yellow Charlene Strawn, the beautiful white Marliacea Albida, a prolific bloomer, or the colorful Red Spider with its narrow red petals are all popular selections. You could also add tropical day bloomers, such as the Blue Beauty, a fragrant old standby, or the Robert Strawn with its lavender flowers that hold high above the water. You may want to consider adding a tropical night bloomer, such as the deep pink Mrs. Emily Grant Hutchings, another prolific bloomer. An extra exquisite touch, in addition to the aquatic plants, is to plant flowers on both sides of the waterfall also. This not only adds beauty, but also helps to hide the plumbing, liner, and excavation. Unless you want to be replanting those plants each year, avoid annuals in favor of perennials. Choose some that will bloom in the spring, such as Azaleas, and select summer bloomers, such as Day Lilies as well.

Enjoying your new water garden with waterfall:

Pour a glass of your favorite fine wine and relax in your most comfortable patio chair surrounded in the serene, sensory delight that is your new water garden. Allow the lilting sound of the waterfall to lull you into peaceful tranquility. Watch the summer sun set against its orangengolden sky as dusk's canopy is bedazzled with the glitter and twinkle of fireflies in flight. You are mellow. Life is good.