By Carolyn Weise
The benefits of a waterfall are many, as are streams, however they are generally chosen for aesthetic purposes. The sound of running water, the natural feel of water running through the garden, and the reflection of birds, sunlight and flowers have a relaxing effect on our blood pressure and other senses. What is not as well known is the benefit to the pond. The moving water actually gathers oxygen as it travels over rocks and splashes into the pond. Of the waterfall and stream, the stream is probably the more efficient oxygenators of the two. But the waterfall remains the more popular. Let’s first look at construction of a waterfall.
WATERFALLS: When building a waterfall, it is helpful to consider water direction and flow into the pond, as it is to be a big part of the circulatory process. A healthy pond does not have ”standing” water, but is continually moving every part toward the drain and filters to be cleaned and refreshed. Therefore, the angle you choose and the placement should be farthest from the skimmer and filter intake unit (bottom drain). The height of the waterfall will depend upon the size and surface area of the pond. A tall heavily splashing waterfall will empty a small pond quickly, therefore too much splashing should be avoided. By proportioning the falls to the pond you will have a better system and fewer problems. Almost all pond leaks can be traced back to improperly constructed waterfalls.
A reservoir at the top and bottom of the waterfall will not only help contain the water, it will also offer a place for more rocks as an aid in oxygenation. Plants can be added to the top of the falls. The first step after determining the site for the waterfall is to build a foundation, for which cinder block or concrete blocks work well. This will be set in place, mortared to smooth out any rough edges, and lined with EPDM liner. It can then be ½ filled with sand and smooth stones, leaving a shallow pool for gathering water. There is nothing pretty or natural about water spurting out of a PVC pipe. All liner and pipe work should be covered by rocks, and the liner must be higher than the water level to prevent future leakage.
When adding a waterfall to an existing pond, it is best to overlap the liner into the pond rather than to try tucking them together. The water will “wick” out between the two pieces of liner if they are together. It is also very difficult to glue two pieces of liner, especially if one is already used, without leaks. Arrange the waterfall rocks so they overhang the pond for a more natural look and match the waterfall rocks to the ones used in constructing the pond.
Tip: Use a variety of rock sizes, rather than uniform size, as it will look natural if there are, for example, large boulders and very small rocks together.
STREAMS: Streams are incredibly useful as bog systems, vegetable filters, oxygenators, and are attractive to wildlife. A woodland-type stream can be made with EPDM liner and muscle power.
Bring in dirt, or dig and move, to build up an area, 15-30’ long and 5-6’ wide. Use stones to support the dirt along the sides and hollow out individual pools in the stream bed. Each pool should be 3’ deep and 4-5’ wide. Leave partitions of dirt between them, and have each one lower than the one before, going down toward the pond. Start at around 4’ high for the first one. The partitions between each pool will be spillways from one into the next.
Then stretch a liner over the entire stream, leaving 2’ on each side, the top and bottom. Mold it into each pool carefully, and ½ fill with sand and a layer of smooth stones. Place a flat rock on the spillway, at the waterline for each pool. This will assure a good flow. Be sure to use a level and have the sides higher than the spillway, or the water won’t go where you planned. The sides should be 3-4” above the spillway and waterline levels to prevent water loss.
Then tuck in the liner, in and under rocks along the side of the stream. The water line will enter from the top of the first pool, and should be hidden by rocks. It must be secured so the water cannot go anywhere but into the first pool. Bury the line back to the filter or pump.
Plants along the stream will add to the natural look and those used in the stream will become vegetable filtration for the pond!
Tip: Install knife valves for winterizing, or diverter to underwater return, so the stream and waterfall can be shut off and prevent super-cooling the pond when temperatures drop below 50ºF.