In the last two weeks, we’ve been talking about water features, specifically ponds, and how to construct them. This week, we’ll talk a little about waterfalls and streams, and the pumps and filters required to run them.
For either a preformed waterfall or one made from a flexible liner, you must make sure the mound of dirt that will hold your falls is firmly packed. If not, it will settle over time and your carefully planned water feature may cease to spill into the pond.
Before you begin, make certain the pond receiving the water is large enough to hold it all when the pump is turned off. And with either a flexible or a pre-formed liner, be sure to test your layout once the liner is in by sending water from a hose down its length before completing the project.
If using a pre-formed waterfall, excavate the earth to fit the unit. Depending on its size, you may have a single piece or it may come in several sections. If in sections, it’s a good idea to use a plastic liner underneath. Once you’ve hose-tested your configuration, a few dollops of cement on the bottom of each section will anchor them nicely.
Finish off the waterfall with stones along the inside edges. Then, backfill around the units with damp soil after installing the necessary plumbing to re-circulate the water.
When using a flexible liner, begin by laying out a course with a length of hose or string, or use a rake to draw a flow pattern directly on the mound of dirt, incorporating twists for added interest. Next, drive in stakes to mark the site. As you excavate, create a series of steps to guide the water down to the pond, taking care to ensure the steps are level from side to side.
Spread liner protection fabric or a two-inch layer of sand and then spread the liner, cut to fit the entire waterfall with a one-foot overlap on all sides. Then, beginning with the bottom step, lay a flat rock so that it overhangs the edge of the pond. Then fit in a flat rock riser and continue the pattern up the waterfall. You’ll also want to line the edges of the falls with flat rocks. Once you’ve used your garden hose to test the flow of water down the course, mix cement with a waterproofing agent, tint it to blend in with the rocks, and spread in the gaps to seal them.
With a flexible liner, you have control over the path, the sound, and the visual design of your waterfall simply by adding and moving large and small rocks. Experiment until you get the sound and flow that pleases you.
There are a number of books on creating ponds and water features in your yard that include information on necessary plumbing and its installation. I highly recommend consulting one of these for more in-depth information. But, here’s a quick overview of some of the basic plumbing materials you might need.
You may not need a pump for a small pond unless you want a fountain. In that case, you’ll need a small, submersible unit to drive the jet. Many of these come complete with several fountain choices.
Although every pump manufacturer will supply electrical information – amps and horsepower – the most important information in choosing the right type and size pump for your specific application is the volume of water it will pump vertically. This will give you the number of gallons per hour that a pump can move at a given height.
For waterfalls and streams, you must calculate the amount of water you plan to move. Use a garden hose adjusted to a flow that approximates the desired volume. Collect the water in a five-gallon bucket for one minute, and multiply that amount by sixty to get gallons per hour. If you’re equipping a larger system, you may have to hook up a temporary pump to calculate the amount.
If your pond has the proper balance of plant and animal life, it may not need a filter. But several common occurrences may require a filter to keep the water clear. These include excessive light, overfeeding fish, and fish waste. In addition, if your pond does not include plants, a filter will be necessary to eliminate algae.
Mechanical filters strain the water but do not purify it. Biological filters use bacteria to convert ammonia and nitrites to nitrates as part of the nitrogen cycle. Often, people use a combination of the two.
This is just a quick overview of the main components. Remember, if you have a waterfall or stream, you will need tubing or pipes to recycle the water. Depending on the complexity of your design, you may also want or need underwater lighting, a ground fault circuit interrupter (GFI), and a float valve that ties into a nearby cold water pipe to top off water lost to evaporation and over splash.
Next week, we’ll get to what I consider the good part – your reward for all the hard work (it’s not really too hard) – the plants.
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