Building a Pondless Waterfall
I can’t think of a homeowner who hasn’t dreamed of owning a water feature. The same thing that compels a person to travel hundreds, even thousands of miles to gaze at Niagara, Victoria or Iguazu Falls fuels the desire to create one’s own mini-Niagara, right in his own backyard. There’s just something about the sight and sound of water rushing over rocks that soothes the spirit.
Having your own waterfall used to be something only a wealthy person could experience.
Not anymore. Thanks to technology, anyone can afford to have a modest water feature. And now that the economy has perked up again, homeowners are back in dream-fulfillment mode. A pondless waterfall is the perfect thing to suggest to such a dreamer. It’s a relatively inexpensive way that an ordinary person can enjoy this luxury.
A pondless waterfall is just that, a water feature without a pond. A deep hole isn’t needed, and because you don’t have to excavate a deep or extensive one, the time and labor involved is much less. A small reservoir hidden just belowgrade is filled with water. A small pump in the reservoir pumps water up to the top of the falls. The water tumbles back down via gravity and is pumped out again, creating a closed circulation system.
However, before you begin building, you first have to decide where this feature should be placed. Ideally, it should be positioned so it can be seen and enjoyed from inside the home as well as outside. If the client has an outdoor living space, it should be integrated into it. (If he doesn’t have one yet, this could be the start of something much bigger!) Now, to build it. You have a couple of choices.
If you’re new at this game, you might want to consider buying a kit. They come in a variety of sizes and styles, and can really streamline the whole process for you. Your local wholesale distributor should carry them.
All the components—the modular geosynthetic blocks, pump, liner, underlayment geofabric and everything else you’ll need— will be included in the kit. Or, you can purchase the components separately and build it from scratch.
But before we grab those shovels and start digging, let’s take a look at the soil. A house needs a strong foundation, and so does a water feature; water and rocks are heavy. If the soil underneath it isn’t stable, when the soil does settle, it can cause the waterfall rocks to shift. So if the soil is loose, make sure you compact it before you do anything else.
Once you’re certain you have a good, stable base, you can start your excavation. The reservoir area should be big enough and deep enough to hold all the water needed to circulate through the system, about 100 gallons, at minimum. Make sure the reservoir has enough extra capacity to hold on to the water when the pump is shut off; you shouldn’t see water flowing over the sides.
The reservoir needs to be just deep enough so that the water will cover the 15-inch submersible pump and the 15-by-19-inch blocks completely, and keep the blocks even with the grade. You can include a deeper area in the reservoir to insert the pump vault, if the pump vault’s height requires it. If there’s a hill, make sure you’re building your spillway on the high side of it.
If you’re installing the feature in a substrate that tends to retain water, such as a dense clay soil, you may need to create drains underneath the liner. This way, should you ever get a heavy rain or groundwater buildup, these escape hatches will prevent the excess groundwater below from pushing the rocks and modular blocks up and out of place.
Next, level the top rim of the reservoir. This can be done using a straight piece of lumber, such as a two-by-four. Lay it across like a bridge spanning the reservoir, and put a bubble level on top of it. If the top rim of your reservoir isn’t level all the way around, make it so. Then, level off the bottom of the reservoir so you’ll be able to place the blocks flat into it.
Before we put anything into the reservoir, though, we first must put down the underlayment. This is a sheet of geotextile fabric that goes underneath the waterproof EPDM liner and protects it against any rocks in the soil that could tear it, and compromise your water feature’s foundation. This underlayment step is crucial, so don’t omit it.
It’d be like installing carpeting without a pad.
Once you’ve laid down the geotextile fabric, lay the EPDM liner down over it, and smooth it out as much as possible. Push it down into the reservoir, smoothing it into the corners and over the sides.
Now that you’ve prepared the reservoir, you’ll put in the modular geosynthetic block products (AquaBlox, Eco-Blox or others). They’ll create a strong base for the rocks that’ll be put atop them, to hide them from view and naturalize the look of the feature.
You can use marble or golf ballsized rocks, but avoid ones that are small enough to fall through the holes in the blocks. If you wish, you can put fabric cloth, plastic mesh with three-eighth-inch openings, on top of the blocks before you add the rocks as extra protection.
Avoid making the common mistake of cutting the EPDM liner too short; you’ll have nowhere to go if repairs or patching are needed later. Besides, the weight of the water and everything else in it will cause the reservoir to settle over time. So, leave a foot or two of extra liner material and fold it over. It’ll be hidden under rocks and plants anyway. It’s best not to cut the liner until after you’ve seen the feature running.
Place the modular blocks and pump vault in the reservoir, to serve as a base for the decorative rocks and boulders, then fill in the remaining spaces with rounded river rocks. To protect the integrity of your liner, avoid using jagged-edged rocks or gravel. Experts also advise against using pea gravel here, as debris tends to build up in it, and can eventually prevent the water from reaching the pump. Use rocks no smaller than fist size to fill in around the blocks.
Place the pump in the reservoir and connect the pipe to the spillway. The pump is the most expensive component in the entire structure, so it’s important to keep it from burning up, which is what will happen if the water level gets too low. To prevent that, it’s a good idea to install a low-water shutoff switch.
This way, if the water should ever dip below a certain level, the pump will automatically shut down.
Now comes the fun part, aesthetically placing the decorative rocks and boulders around the feature, to make it look like a natural part of the landscape. Submersible, remotecontrolled LED lights can be placed along the rocks in the waterfall, giving it a dramatic look after dark.
Once the boulders are placed surrounding the waterfall, you’ll notice some voids at the points where they meet. Many installers fill these with black expanding foam so the water doesn’t run into them. But don’t overdo it, especially around the edges, or you risk having water flow over the sides of the feature.
Fill the rest of the bed with river rocks. Finally, install plantings around the edges of the waterfall. Include some that are already part of the landscape so that it blends in seamlessly. Start the pump and watch your waterfall in action!
Now, let’s look at what’s required to keep it going. This type of water feature requires minimal maintenance. However, low maintenance doesn’t mean no maintenance.
Water should be added every week or two to offset what’s been lost to evaporation; make sure the client is aware of that.
Once-yearly cleanouts are usually sufficient in warmer climates. Setting up a routine maintenance contract with the client to service the feature at regular intervals will help keep things running smoothly.
In areas that are prone to freezing, you may need to winterize the feature by disconnecting the pump and storing it indoors. Once the pump is disconnected from the pipe, make sure that no water remains in that pipe, or it could freeze and break.
Some people in colder climates run their water features year-round, using the friction of the running water to keep it from freezing. If this is the case, you might need to dig a deeper hole. Burying the reservoir at least four feet underground should get it below the frost line, where the geothermal activity of the soil should keep the pump from freezing.
Installing a pondless water feature is a wonderful way to bring added beauty and delight to your clients’ backyards or outdoor living spaces. In just a few short hours, you’ll be giving them something they will be able to enjoy for years to come. And, maybe even silently thank you every time they look at it.